I have no doubt Ainge did his "due diligence."
There were also other considerations: the inputs of Stevens and Wyc, for example.
Stevens does not value bigs as much as others. Maybe he didn't value Davis. And Davis gets hurt frequently. He misses games.
Maybe the money was prohibitive in terms of re-signing him. That could be a bigger concern than actually re-signing him. Hayward's contract is an albatross right now. And with Irving coming back, it might have been excessive.
Maybe he didn't want to give up all those draft picks he's hoarded, particularly for a rental.
Some of us view a dominant big like Davis as critical for the Celtics success. I doubt Ainge/Stevens share that view.
I'm sure they weighed all these things carefully, and decided not to throw the dice.
I doubt that. I just think Rich Paul's comments killed the trade for the Celts. The OP brings up a good point though. Shouldn't Ainge have seen this coming?
Let's say, just for giggles, that Ainge saw it coming a couple years ago, or even a year ago, and decided not to get involved in trade negotiations. How do you think he would be perceived by the fandom with the fans wanting him to go after a star and there being noise in the media that Danny was passing on trying to make the trade?
Ainge obviously wouldn't be able to comment on it. Speculation would have gone wild and the fans would have turned on Ainge for showing no interest.
Instead, Ainge did everything he could to close the deal but decided not to do it because, the price was too high and there was no guarantees Davis wouldn't be anything but a rental.
Either way, people aren't happy and complaining about the guy.