(Sidenote: LeBron will be reeeeal effing happy about this - his new running mate missing training camp, etc...)
If you max out a guy like him next offseason it will bite you in the butt so hard... likely lose your job becouse of it sooner or later.
While the guy balled his heart out, it's just an unfortunate situation for him (and a bit for Boston as well, as this makes them look bad, and not loyal).
Ainge even said somewhere after the season that they did not really achieve anyhting in this season b/c of the conference they are in, and the fact that 1-2 bounces go the other way and they could be out of the playoffs in the 2nd round against Washington (or Toronto, or whichever 2nd tier Eastern team) this year or next yr. And we haven't even talked about the Warriors. I have to agree with him.
That's life. It might not be fair, but it is what it is. Midget lead teams dont win it all in the NBA. Not with AI, nooo way with IT.

Now if I'm Ainge, I'm all over trading Horford (with any picks, players that might be needed) to get a difference making bigguy - like Boogie. That's a legit big3, round out the rest with whatever is left of Smart/Rozier/Semi/Brown/Tatum/Morris, a cpl 2nd rounders (or what you have left in Allen/Bird/Baynes/Larkin/Yabusele), get a cpl veteran minimum guys, let Stevens do his magic and take the east easily in the next 3-4 years - with a bit of injury luck they might win one chip out of 3-4 tries.