I don't think it's as much age concern with IT as it is his serious lack of height. His most lethal weapon is, as I said, his speed. But once he loses that, he's done because he doesn't have the height to create anything, just his speed. Add in the fact he is due a payday in a year and that this hip injury could be much worse than anticipated and it makes a lot more sense to ship him off. Every year he ages is lost speed. That is the first thing to go.
Think of it this way, you're not building to beat just the Cavs, you're building to beat the Warriors. What better way to do that then a guy that already has a GW shot in Game 7 against a 73-9 team on his resume. A guy with size, speed, and similar IT scoring ability. He has proven he can torch the Warriors. Thomas has proven he cannot do anything to damage the Cavaliers. You stick Lebron on him and that is that, he's done.
I love IT and I will miss him but this trade was necessary for the future of the organization. Hopefully now they can sign Kyrie to an extension, make a serious go at Anthony Davis in the near future or some other bonafide superstar, and continue to build this team which is quickly becoming quite good.
Lost in all of this is maybe Boston will try to bring him back next summer. That's always another possibility. There's a very high chance IT does not stick around in Cleveland for very long. He's going to get paid by some team. Even if it's not a powerhouse, a desperate team with money will overpay him. So the Cavs better make great use of that pick or they lost Kyrie for virtually nothing.
Also, you have to remember that IT was the FACE of the Celtics. I can say with pretty high certainty that he will not sniff those numbers playing second fiddle to Lebron. The Cavs are not his team. The Celtics were his team. Almost all of the offense ran through IT. That is no longer the case. I expect a drop in production automatically based on that.
Kyrie got 25 ppg playing second fiddle to Lebron. Let's see what this guy can do with his own team now. Because they are going to be his team, I'd imagine.