This is ridiculously far from the truth.
I think drafting is his weakest area as a GM, that does not mean he is bad at it. But he has missed some guys, all GMs do. It is not so far from the truth as I see it.
Most of his great players have been trades, Bradley is about the best guy he has drafted. He seems to be better at drafting guards too than bigs.
That being said, I love Ainge as a GM, he is a hard bargainer. It is like having Tywin Lannister as our GM.