Danny didn't trade for Davis so he must not have done his due diligence is a false equivalent. Ainge did his due diligence and decided making the move was not in the best interest of the Celtics.
Ainge gets involved in just about every big trade that could be happening. Heck, there were reports he was talking to Houston, when the Davis deal was still an ongoing thing. Obviously, he was looking at other options, i.e. doing his due diligence.
You do not WAIT three years for a player that is not coming. I am not talking about due diligence he did in the last six months. I am talking about due diligence he did when he decided that it was Davis or bust, which if you follow these blogs everyone seems to think he made years ago.
Name one legitimate source that says Ainge passed on other trades for 3 years waiting for Davis to become possible. You can't because the premise is absurd; he traded for Kyrie just 2 years ago, which by definition was cashing in our assets, even if the cupboard wasn't empty afterward.
The whole Davis or bust narrative only became a talking point this year, and it was fodder for the blogs, which you've made clear is your only source. Prior to that, of course Ainge lusted after him, as he should have, and as every other GM in the league did. We're talking about a guy who's a top-5 player just entering his prime, a big who can play inside and out.
The truth is that the Lakers made a ridiculous offer. More power to them. I still don't think it guarantees a title or is cause for the angst tonight. Just like Horford wanting a 4 year deal, Danny didn't think it was the smart thing to do long-term.
Ainge has been right virtually every time fans questioned him.