Do I overestimate Smart and underestimate Porzingis ? I don't know. Maybe you do the opposite. We will see, if we don't win it all and Porzingis leave for nothing (or trade exeption, wgich always turn to nothing but hope for us) it will be a bust for Brad (or a dumb of salary for an all time celtics).
It's even not about the draft picks or the fillers (Muscala or even an old and 1 year unactive Gallo). Porzingis is more talented offensively ? Of course. Do we need a long term big option to take Horford role. Yes sir. But it is still a bad trade for me, the argues are too strong AND TOO SIMPLE to overcome.
It's about PO's. Porzingis had 3 great match and 7 horrible one the year later (was he hurt ?). At 27 it is thin, easy to say it is because he was always on the worst teams of the league. He wasn't. I don't even have to argue to the long run PO participation, with Smart, even with unproven grit teams like IT one.
It's about value. He leaves all his teams with little value, embarassing contract, due to injury or not being what expected (next to Doncic and a correct core). He was traded for role players or/and fillers. He doesn't had a great reputation before being good on the big 3 of a mediocre team. He still hasn't more value for them than Tyus Jones and filler, which tell some.
It's about complementarity. Smart was giving some things we lacked and still lack. Effort, voice, experience, intensity, hard playing, versatility in defense. Tatum and Brown have it ? Porzingis ?
It's about playmaking and IQ. Smart wasn't ideal. He wasn't the floor general, but a very good captain. And mostly he has quiet good IQ when he doesn't fall in hero ball (like Tatum and Brown stinked some times also). White isn't a point guard. Brogdon isn't a good passer for a point guard. He is playing for himself like Kemba did. Tatum makes effort and improve in that way but has more of the mamba mentality. Don't even speak about Brown or Porzingus. Some talk about Pritchard or Davison. No. We are contender not in building our playmaking identity.
It's about defense. Maybe Smart regressed. Maybe also because of Mazz. Personnally a core of White-Brown-Tatum-Porzingis-Horford/Timelord could be good defensively, but the outside defense is questionning, a problem we had in this PO. More do you imagine the structure of the game with 3 desperados ?
So maybe there is a trade but maybe this also save some millions if next year we don't resign Smart while we are signing Brown. Hope it isn't that.