So I do not think we should view the trade in the lens of:
1. Is JB a better player than PG?
Because they are not equal. JB is clearly superior and that is why picks were added. We can debate whether the draft haul was good enough or not (I honestly wish there was one more first added) but it is close, I think. I do not think JB had a market of promising young player + 4 picks. I think JB had a market of either promising young player OR 3 picks. If they were of equal value, then it would have been a straight trade for JB and PG. Stop comparing JB and PG.
2. PG is earning the same amount and provides no flexibility
This is also flawed. What PG brings most to the table in the trade is making the money work for a shorter time and resetting the tax. PG waiving his clause allows us to stay under the tax and allows us to reset the tax and I suspect this was discussed and agreed upon beforehand. I doubt it was Brad Stevens praying for PG to just waive it. PG will also be a trading chip for teams looking for some relief next year.
This is a future looking move.
Current timeline: You have one year of PG, you reset the tax, and then the next year, you have your flexibility. Celtics can pursue free agents (idk who) and they can spend without being punished too much.
Alternate timeline: You have 5 years of Brown and Tatum. In those 5 years, you will eventually need to shed players like White and Pritchard because the CBA is just so punishing. Can you win with Brown and Tatum and a worsening supporting cast without much draft capital to bring in reinforcements? It seems our front office did not think so
We need to accept we are in a new era. There are no more dynasties and no more long contention windows. Teams need to retool quickly or players need to start taking pay cuts. Even teams like OKC will crumble soon because they just will not be able to justify keeping all their good players. It will be a long time before we see a team as stacked as the 2024 Celtics and even then, that team is probably only going to be together for 1-2 years max.