BOSTON — The most encouraging moment came after it was over: after they'd almost unraveled, and then clawed their way back, and then left a sellout crowd screaming in relief that they don't make the games a few seconds longer. Ben Simmons climbed atop the podium and looked back on his series and spoke the kind of words that legitimize dreams of the future.

"I'm still learning," he said. "This is just the start for me. … There's a lot of things I learned this series that I didn't learn against Miami, and that makes me a better player."

If they were going to lose, this was how they needed to do it: unequivocally. They needed it to be an expose, a revelation, a thorough accounting of who it is that they really are. For a week-and-a-half, it was all of that, and on Wednesday night, the Celtics finished it off with an exclamation point that should echo through the Sixers' offseason.

This wasn't a series so much as it was a self-inventory, a report card, a 50-point inspection whose conclusions can now be stated with no uncertain terms.

1) This is not yet a championship roster.

2) It is not yet particularly close.

If either one of those statements makes you bristle, consider the point proved, because neither one is the least controversial for a team at the Sixers' juncture. They are good, damn good, and resilient to boot. You saw it over the course of the series. Each game they improved, adapted, learned on the fly. That says something about the timeline that Simmons and Joel Embiid and Dario Saric are on. It has moved faster to this point, and it could continue to do so.

"They're special because they just keep coming," was how Boston coach Brad Stevens put it.

But they haven't arrived yet, and the best thing about this series is that the conclusion is clear. That's the victory that occurred in the second playoff series of what should years' worth of runs. Short of a berth in the NBA Finals, the best thing this postseason could have yielded was a reminder to the Sixers of the reality of their situation. Lurking beneath all that the Sixers accomplished this season was a danger inherent in any preternatural success. Self-delusion is a destructive state of mind and winning 52 games and a playoff series is an easy way to inhabit it.

By the end of a 114-112 loss to the Celtics that sent them home for the summer, the exact nature of that reality was impossible to ignore.

It starts with Simmons, who made things look easy enough throughout the regular season that it was fair to wonder whether he would fool himself into thinking that's how easy they are. More than anything, his performance this postseason should lay to rest any such notion. This was somewhat true in the first series, but in the second there was no doubt. The Celtics spent all five games walling him off in the transition game, and packing the lane in the half-court. They dared him to shoot, and he didn't, and the result was one of the game's most electric rookies looking too much like a bystander in too many possessions.

That's a good thing. Repeat it again. Because for Simmons to achieve his potential, he was always going to need to expand his offensive game. Maybe he'd already realized that, but there is certainly a chance that he did not realize the extent of it. Throughout the regular season, asking him about his reticence to shoot was one of the few ways to elicit a bristle in his flat-line facade.

Against the Celtics, though, the lack of a jumper was a serious issue, the primary reason they were able to take away his angles and clog his path to the rim. Without their point guard's ability to penetrate, the rest of the Sixers' offense looked like a flat tire. Their shooters were blanketed, their big man smothered. All of it starts at the point.

That is the first lesson: that Simmons needs to start his summer early and spend all of it attempting to develop some semblance of a jump shot. That might require a significant mechanical change, rotating the flared elbow on his shooting arm in to remove the tilted spin on the ball that acts like kryptonite on the rim.

The second lesson is for the men in charge of building the roster. Against the Celtics, it was obvious that the Sixers need the player that Markelle Fultz was supposed to be: a two-way combo guard capable of spacing the floor with a jump shot, penetrating to the rim, and playing defense against the big, athletic perimeter players that a team like the Celtics throws at you for 48 minutes.

What the Sixers did not learn is whether Fultz will be that guy, and it's difficult to envision them doing so before the time comes to make some critical offseason decisions. JJ Redick was everything they hoped he would be this season, but they hoped that they would be able to supplement him with a more athletic guard who could shoot and dribble and matchup on defense. Against the Celtics, the Sixers learned that they need to find a player like that in case Plan A continues to falter.

They also must replace Redick himself, either by re-signing him or by finding another shooter of his caliber. They might need two such players, since Marco Belinelli will also be a free agent.

There are a lot of directions they can turn. You'll hear plenty of talk about LeBron James this offseason, but there's a case to be made that Paul George is a better fit, perhaps as an upgrade to Robert Covington that leaves Dario Saric in the lineup.

There will be plenty of time to dissect all of these things. Yet as the Sixers packed up the visitor's locker room and prepared to head south for the last time, October was just five months away. They did so beneath a significant silver lining: the knowledge of the things they need to do to make next year last a little longer.