I am not the slightest bit worried about the Sixers ever being a threat to the Celtics. They're like 6 players away from fielding a competitive team, by the time their draftees are all good enough, some will become too expensive to keep.
They're much more likely to wind up being a slightly better version of the Wizards.
Funny that these arguments about retaining rookies only get applied to the Sixers even though they have the best cap space and shouldn't have a cap issue for many years. Assuming that Embiid stays healthy and Simmons comes close to his projections, the Sixers should be in great shape. If they get really lucky and have 4 rookies deserve MAX that is only 100% of the cap to retain them all. Or more likely they'd trade the least of the 4 away for good support players and/or picks.
Why not raise the issue about the TWolves? Their cap space is much worse and their rookies hit free agency sooner. They already had to extend Dieng. This offseason they'll have to decide on retaining Muhammad and on extensions for Wiggins and LaVine. The Lakers are worse off than the Sixers too.
1) Because it's a Sixers thread.
2) Because the Sixers play in the Eastern Conference, and thus what happens to them affects the Celtics more than Minnesota or even LA.
3) Because people thought Minnesota would be better than they are. They weren't supposed to be staring yet another high lottery pick in the face -- it's unclear which of their young players they should even try to keep on long term deals aside. But since you're concerned with them, yes, they are facing a similar situation.
4) As for the Lakers -- they will have no problem spending into the luxury tax to keep the players worth keeping, and will have less trouble attracting free agents if their roster turns it on in time for the summer of 2018. They are not in the same situation.
How many players on the Sixers roster do you think will still be on the team when they make the playoffs again? Two? Three? I think it's just Embiid and Simmons. And that's assuming that Simmons pans out and Embiid stays healthy. They are a bad team of mostly replacement-level NBA players, and are so many pieces away.