Players don't care about the Celtics mythos anymore. Boston is viewed as a shitty and whiter New York with a bunch of banners stemming from bygone eras.
Ainge played the draft perfect with regards to his young superstars (which he could do via Brooklyn trade) and held onto his assets for a long time, when people killed him for it. He built one roster that was title worthy and this one seems to be pretty damn close. Is he a great GM? He's probably in the arena. I do think the mentality of not being scared (which most GMs are) is correct. He's not scared to make a mistake or make bold moves, even though bold isn't always good.