Parsing from byennie post:
Brad thought: Jaylen needs to go, he's not a supermax guy, we're hosed if we keep him, my analytics tell me...
I agree with this. BOS came to the conclusion that they had gone as far as they were going to go with Brown on a max deal and what they would be able to put around Brown and Tatum, and did not want to extend him and lock in 5 more years of more or less the status quo. They decided to try and trade him for Giannis, and maybe some other teams prior to that.
Brad also thought: Jaylen is a Finals MVP, All-Star, marketable, in his prime, and SOMEONE is going to pay a star price for him,
Also agree, based on what MEM got for Bane, why wouldn't BOS feel they could get at least as much for Brown? I guess all the other teams have analytics departments too and they all came to the same conclusion as BOS, Brown is a great player, but not a player you want on a Max deal for 5 years. Bane makes a lot less ($39M to $58M). I think that is the obvious difference here in how the two players were valued.
Just because Brad may have overplayed his hand, doesn't mean more was available.
Exactly, I don't know but I don't see why a team that liked Brown but didn't think he was worth (4) firsts wouldn't still try beat the PHI offer. I think what happened was that things were sort of OK last season when maybe BOS and GSW talked. But with all the hoopla around the Giannis trade, Brown got miffed (understandably), maybe started going around telling teams he wouldn't extend (possible including MIL), and Brad/Owners got to the point of just wanting to trade him, potentially leading to them taking less than the absolute best possible deal had they waited (the last part is speculation, no one can know this part either way).