Edit: upon re-reading I'm not sure how much we disagree or not. I really can't tell if you were trying to say coaches didn't deserve much credit. But the C's didn't have a bunch of free agents waiting to get paid when they were playing well.
I think the coach had a part to play, but I think having a constantly shifting roster of guys eager to prove themselves (and earn their next paycheck) played a big part.
Mostly I was responding to the question about the Celts having better players than the guys on all of those other teams.
I think the Celtics have a worse roster than most other teams in the league when you're looking solely at talent. But there's more that goes into how many games a team wins in the regular season than just the talent on board.
You're right that only Bass, Jerebko, Datome, and Crowder were playing for free agent money. Pressey can be added in there, though, because his deal is non-guaranteed.
That's a big chunk of the guys who were playing at the end of the season. Then add in the fact that Isaiah Thomas was eager as heck to prove the Suns and Kings made a mistake in moving on from him so quickly.
I just think it wasn't a surprise that the team generally outhustled and outworked opponents down the stretch. Also not surprising that it didn't matter once the playoffs rolled around.