Cautiously optimistic.
+1
I don't think most of our guys have all star potential, but I think they have a chance to be good, solid pros. Given where they were selected in the draft, that's about all you can reasonably hope for.
Since when does their draft position have anything to do with their potential? There are loads of guys who slipped to the late 1st and 2nd rounds, respectively, who have turned into all stars. Look at Lance Stephenson. No, he didn't make the all star team last year, although he probably should have, but he's one of the best young players in the game, and he was taken at number 40 in the 2010 NBA draft.
Answer: Since the draft was first invented.
Potential isn't the _only_ factor that goes into where a player is drafted, but it is probably the biggest factor. Obviously, gauging a player's potential going into the draft isn't an exact science. So you get exceptions. But overall, most players end up with careers that correlate with where they were picked.
The key to success with the draft aspect of team building is to extract more value out of your allotted draft slots relative to how much value other teams are extracting out of theirs.
Danny hasn't always managed to do this, but for the most part he has stayed ahead on this -- most of his drafted players that he's kept would rank above their actual pick if you did a redraft of their class. And most of the ones where that would not be true, he has managed to unload via trade for other players. Yes, he's missed on some that he couldn't unload for better value. It happens.
Right now, on our current roster, based on most metrics, Sully, Olynyk & Bradley would all rank much higher than the slots where they were drafted, relative to their draft classes. Rondo obviously crushes that scale. 'Way too soon to know about Smart or Young.
That's not saying that all or any of our young draft picks are necessarily going to be 'stars'. But that means the Celtics have managed to extract much more value out of the draft than the average team, relative to where they picked.