Why have the Celtics soared while the Sixers keep processing? One team has been shrewd.

There was a time, not too long ago, when the 76ers’ future appeared brighter than that of the Boston Celtics.

Smart decisions in Boston and mistakes in Philly — especially in the NBA draft — have left them in disparate places.

Boston hosted the Dallas Mavericks in Game 1 of the NBA Finals on Thursday night — a 107-89 Celtics win — and is in the midst of its second Finals appearance in three seasons. Meanwhile, the Sixers have several roster spots to fill after being eliminated by the New York Knicks in the first round of the playoffs last month, continuing a streak of 23 seasons without a trip to the Eastern Conference finals.

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The last time the Sixers advanced beyond the second round was 2001. Since then, they have made 14 postseason appearances, including seven straight. However, they have stalled in the second round, falling in seven games at that stage in 2019, 2021, and 2023.

The teams’ differing playoff experiences can be linked to one fact: The Celtics got it right in the draft. Boston selected Jaylen Brown and Jayson Tatum with the third overall picks in the 2016 and 2017 drafts, respectively, and they have become the cornerstones of the franchise.

In Philly, Joel Embiid, picked third in 2014, has been the lone lottery pick to pan out. And there was even luck in securing Embiid, the league MVP in 2023 and a seven-time All-Star, and Tyrese Maxey, the only other first-round pick on the team.

In fact, the Sixers’ 2013-14 season was tanked in hopes of drafting Andrew Wiggins. There was even a fan slogan: “Winless for Wiggins.”

But Embiid slid to No. 3 behind Wiggins and Jabari Parker because of a navicular bone fracture in his right foot that caused him to miss his first two seasons.

Wiggins, a one-time All-Star, has played for three teams since the Cleveland Cavaliers selected him with the first pick. While a suitable starter, the Canadian is not a franchise-altering player.

Parker, selected second by the Milwaukee Bucks, was a role player for six teams during eight NBA seasons after injuries limited his lofty expectations. He played this season for FC Barcelona of the Spanish Liga ACB and the EuroLeague.

Maxey, one of the league’s young stars, fell to the Sixers with the No. 21 pick in the 2020 draft. He was named most improved player and became a first-time All-Star this season.

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“I think he probably exceeded [my expectations] in that the step he took this year was extremely hard, and for sure not a given that he would have done it,” Sixers president of basketball operation Daryl Morey said of Maxey. “We should all learn not to bet against Tyrese given that he’s beat expectations every single season, both prior to coming here and then here.”

But the Sixers can’t say the same about former lottery-pick acquisitions Nerlens Noel (2013), Michael-Carter Williams (2013), Dario Šarić (2014), Jahlil Okafor (2015), Ben Simmons (2016), and Markelle Fultz (2017).

They probably also wish they didn’t trade Mikal Bridges (10th overall in the 2018 draft) to the Phoenix Suns for Zhaire Smith. Bridges is now one of the league’s top two-way players, and Smith played only 13 games in a Sixers uniform and is out of the NBA.

And the same can be said about parting ways with Jimmy Butler and JJ Redick following the 2018-19 season.

There were mistakes before all that, too.

The Sixers agreed to trade point guard Jrue Holiday and second-round pick Pierre Jackson to the New Orleans Pelicans for Noel and a 2014 first-round pick on the night of the 2013 draft.

Noel, who was the sixth pick, missed his entire rookie season while recovering from knee surgery. Noel, at 6-foot-10 and 220 pounds, averaged 10.2 points, 7.6 rebounds, 1.7 steals, and 1.6 blocks in 171 games over 2½ seasons before forcing a trade to the Mavericks on Feb. 23, 2017.

Holiday, coming off his first All-Star berth when he was traded, has blossomed into one of the league’s best two-way players. The Southern California native is a six-time all-defensive selection, a 2020 Olympic gold medalist, and a 2021 NBA champion with the Milwaukee Bucks.

Now with the Celtics, the veteran of 15 seasons is a major reason Boston is favored to win its 18th title. Holiday, who turns 34 on June 12, will also team up with Embiid on Team USA this summer in the Paris Olympics.

Talk about a huge miscalculation.

While the Celtics are praised for making solid picks at No. 3 in 2016 and 2017, the Sixers have nothing to show after selecting first in those drafts.

It was no secret that the Sixers would select Simmons, the headliner in 2016. But there were questions surrounding his shooting and mentality before the draft.

Looking back, Brandon Ingram was a better fit. The 6-8 swingman, who was taken by the Los Angeles Lakers, can make shots on the perimeter and score off the dribble. Ingram, who spent the last five seasons in New Orleans, is now among the Sixers’ trade interests.

Once paired, Simmons and Embiid did not always see eye-to-eye. Simmons subsequently refused to play for the Sixers during the 2021-22 season, forcing a blockbuster trade to the Brooklyn Nets on Feb. 10, 2022. Simmons, a three-time All-Star, remains limited by back injuries and shooting issues.

During the 2017 draft, Danny Ainge, the former Celtics executive director of basketball operations, swindled the Sixers.

Intent on selecting Fultz, the Sixers moved up two spots. They dealt the No. 3 pick and a 2019 first-round pick to the Celtics for the honor of selecting the guard from the University of Washington with the first pick.

The trade might go down as the worst in Sixers history. The Celtics and Lakers, who picked hometown favorite Lonzo Ball second, had no intention of drafting Fultz. Boston ended up taking Tatum at No. 3 that year and picking Romeo Langford at No. 14 in 2019. Langford was sent to the San Antonio Spurs on Feb. 20, 2020, as part of a package for major contributor Derrick White.

» READ MORE: Daryl Morey must capitalize on the Sixers’ title window. Trading the No. 16 pick is a step in the right direction.

But even if Fultz had been selected third, his tenure in Philly would be remembered as a major disappointment. Shooting problems and considerable time missed clouded Fultz’s time with the Sixers before he was shipped to the Orlando Magic on Feb. 7, 2019.

In exchange, the Sixers received Jonathon Simmons, a 2019 second-round pick, and the Oklahoma City Thunder’s 2020 top-20 protected first-rounder.

The Sixers shipped the second-rounder to Boston during the 2019 draft in a trade that brought in Matisse Thybulle. Then they used the 2020 first-rounder to select Maxey, a steal at No. 21 and one of the league’s rising stars. Thybulle, a two-time second-team all-defensive selection in Philly, was traded to the Portland Trail Blazers on Feb. 9, 2023.

But the mistakes didn’t end there.

After acquiring Tobias Harris from the Los Angeles Clippers on Feb. 6, 2019, the Sixers had the NBA’s best starting five of Jimmy Butler, Harris, Embiid, Simmons, and JJ Redick. The lineup graced the cover of Sports Illustrated on Feb. 25, 2019, with the headline “Process This: The Sixers Are Finally All In.”

The Sixers even gave the impression that they intended to keep the stellar group together.

“We’ve said it repeatedly and we’ll keep saying it: We’ll continue to do what it takes to bring a championship to Philly, including spending into the luxury tax,” Sixers managing partner Josh Harris said.

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But after the team suffered a heartbreaking Game 7 loss to the Toronto Raptors, Butler was traded to the Miami Heat and Redick signed with the Pelicans.

If they remained intact, that Sixers squad would have been favored to win the 2020 NBA title. Instead, the Sixers signed Al Horford, who did not fit alongside Embiid and Simmons and lasted only one season here.

But while the Sixers were breaking up, the Celtics were building.

They acquired players who fit well and played both ends of the floor. And after eight seasons as coach, Brad Stevens took over as team president.

Stevens was named this season’s NBA executive of the year after assembling a team that finished the regular season with a league-best 64-18 record. Two of his big acquisitions heading into this season were Holiday and Kristaps Porziņģis.

And the Celtics should be a contender for the foreseeable future.

Last summer, Brown signed a five-year, $286.2 million supermax extension. It’s the most lucrative contract in NBA history … for now. Tatum will soon be eligible to sign a five-year, $300-plus million supermax extension on July 6. Holiday also signed a four-year, $134.4 million extension in April. The team also harbors hopes of signing White to a long-term deal.

With Porziņģis and Horford also in place, Boston’s core players, who make up the league’s best top-six grouping, are all under contract for at least another season.

The Sixers, however, are in search of a third star to pair with Embiid and Maxey, who is in line to receive a max contract this summer. Embiid, reserve center Paul Reed, and reserve forward Ricky Council IV are the only Sixers under contract beyond this season, with Reed and Council on non-guaranteed deals. The team also has a June 29 deadline to pick up the option on reserve point guard Jeff Dowtin Jr.

They’re still trying to correct major mistakes while Boston sits in position to win multiple championships.