Really, it's that simple.
Is the team aging? Could they have used Perk? Did Jeff Green underwhelm at times?
These are all questions we can debate, but I think most of us would agree that if Rondo had been healthy the past two games, we'd likely be going back to Boston up 3-2 or at least still be alive in this series.
And if that's the case, I don't understand why people want to talk about the window being closed.
KG was All Defensive First Team this year. All three members of the Big Three were All Stars. These are not guys holding on by a thread, these are elite players in the league.
Might they lose a step next year? Maybe. But Rondo might also gain one. Same with Jermaine O'Neal and Jeff Green. If Danny does well in the off-season, this team still has a shot, albeit a smaller one.
But I wouldn't entirely rule them out yet.