I don't think you quite understand how the swap works, or if you do youre being disingenuous about it. The Spurs don't just get the Celtics pick in 2028, they have the option to swap draft positioning. Removing the #1 protection and actually trading the picks gives us two picks in 2028, not just one. 2028 is a long way away and we have no clue where we or they will be. Netting an unprotected 1st instead of a top-1 protected swap is not just a punt.
Secondly...Toronto gave us a 1st for an expiring, undersized C with no offensive game who is terrible on defense just last year and Poeltl is 10x the player that Young was at the time. A team trading for Poeltl also obtains his bird rights and a contender over the cap can re-sign him above the cap while keeping their MLE. He is definitely worth 2 picks to the right team. Even that bum Mozgov got two firsts back in 2015 iirc.
You are right about the pick, but my point is it's a pick we are likely to at least swap for anyway. Better to get the pick outright sure, but it's still a pick we can swap for anyway. And it's so far in the future its a pick that could mean nothing.
I disagree about Poeltl being "10x the player young is". Poeltl has helped do exactly what in San Antonio? Nothing. He hasn't help us win a playoff series, or even a playoff game, or even make the playoffs. He has done nothing to stop us from having a historically bad defense. He does nothing for us on offense but set screens, and you don't need to pay a center his salary to do that.
Talking about what Mozgov got in 2015 is completely irrelevant to what Poeltl can get in 2023. NBA was damn near a different sports back then. Mozgov also played in the nba finals...something I doubt Poeltl ever does unless he is sitting on the bench of a championship team.
It's not that hard to believe tbh