The Celtics in 24 are the only champions since the 1980's to win a championship without a MVP or DPOY on the roster (i.e. a player on the team had won it already). The odds of that happening again are thus very small. So either Tatum needs to win the league MVP, White needs to win DPOY, or they need to trade for that player.
Also, the Knicks are the only team left that doesn't have a dpoy or mvp on their roster. The Cavs have both (harden and mobley), the Thunder have the 2 time mvp, and the spurs have the dpoy. So that string will likely continue again this year.
Someone else already said it but if we trade for Giannis, then BOS will have a past MVP and be able to win a title per the criteria. And the fact that Tatum and Brown won a title together very recently without being an MVP or DPOY weakens the thesis quite a bit. It is not like some random team did it in the past, these specific players did it recently.
I don't dispute that winning a title with Tatum-Brown or Tatum-Giannis is going to be harder going forward than it was in 2024. But the alternative is to go through a period of seasons where the team is totally bad in the hopes that maybe they will come out of it and be good. SAS and OKC were bad for a lot of seasons. DET too. BKN, SAC and several other teams are still bad. PHI has been bad for a really long time and still is not title good.
The way I see it, Tatum-Brown or Tatum-Giannis have a chance to win a title in the next say 3 seasons. If you blow it up, you will be bad for up to 5 seasons, and after all that, you may not even have a better chance to win a title than you do right now. There is a guarantee that the team will be bad, but no guarantee that the team after 5 seasons will be title good. That process is inevitable, I am just not in any hurry to start it.