Let's be honest here, fans get too attached to our own players.
If the C's had drafted Bender, or Dunn, or Murray, or Chriss at #3, many C's fans would think they're untouchable instead. I think most probably wouldn't even trade whoever the C's took at #3 for Ingram at this point. Had the C's drafted one of them though, I think the overwhelming consensus here would be there's no way the C's should trade whoever they drafted at #3 for Jaylen Brown because the player the C's drafted has star potential!
There's definitely some impartial people out there who think Brown would have gone #8 or #9 if the C's didn't draft him (see
here and
here). Had the C's gotten Brown at #8 or #9 instead, suddenly I think some people around here wouldn't think Brown had the same potential. I wouldn't trade a guy drafted #3 for Butler, but a guy drafted at #9 doesn't have the same potential, so ya I might consider trading him for Butler.
If the C's had Jimmy Butler, I doubt most here would trade him for Brown (well except for the few who always seem to want the C's to tank).
It's similar to Marcus Smart. Many of the fans wouldn't trade Smart for Aaron Gordon or Julius Randle either. But had the C's drafted one of them instead and now asked if we should trade one of them for Smart, again most people here would say no way.
It shouldn't matter what # the guy was drafted at or by whom, you want to get the best player. Very few NBA players no matter where they're drafted turn out as good as Jimmy Butler. I would definitely trade Brown for Butler. I don't want to wait and see how Brown develops just because the C's drafted him or he was taken #3, I just want the best player (both now and in the future).
And don't forget for every Joe Johnson for Rodney Rogers or Billups for Kenny Anderson trade, there's a Jeff Green for Ray Allen, a Crowder for Rondo, and a Jefferson/Telfair/Green for Garnett trade.