Considering Danny inherited a no upside roster, dismantled it, turned it into a champion within a few years by acquiring stars that most thought would give us a 3 year max window, I can see why Bird doesn't doubt Danny. That he stretched the 3 year window to 5 years, and then, rather than letting the guys ride off into the sunset with no return, got 4 first rounders for Doc, KG, and PP when it was clear that that nucleus could no longer contend, is more reason for Bird not to doubt him.
Can we point to a couple of bad draft choices? Sure. A couple of FA signings while having very little cap flexibility that we'd take back? Again, with the benefit of hindsight, sure. But the larger story with Ainge is that he inherited garbage, turned it into a championship team, with several more years of legitimate contention, and then sold off declining assets rather than letting them go for nothing. I'm with Larry on this one.