i would just say that most teams who try to do what the Celtics did, suddenly trade a high draft pick and a player who looks like the future, for aged stars in order to compete, will fail and end up in mediocrity. Or make the playoffs but never win a title. There is no blueprint. The Celtics did it their way, but it might not happen that way again. Oklahoma and Memphis have done it (become relevant) by sticking with their young guys and adding the right vet role players, Miami's glue guys are about mid career, etc etc....
There's no formula. Danny recognized that Pierce's ability plus Garnett's defense and leadership, along with one of the game's best shooters ever, were at the point where they would probably succeed due to the above-mentioned talent, hunger for a title and maturity. But they still had to go out and actually sacrifice and do it, which they did brilliantly. There was no guarantee.
I generally like Tommy's approach, which is that you need a mix of vets and young players who push and pull each other.....(by the way, the Celtics need some major pushing this year and possibly/hopefully the year after...)
Bottom line: no one knows what the Celtics next road to contention (post big 3) will look like.
edit: regarding Minny's loss of a high second rounder next year. That hurts a lot. And I'd bet they'd undo the deal to get it back....though I don't know that...