To me, the calculus is very simple.
The C's gave up Thomas plus a lot more to get Irving.
For this trade to be a success, Irving has to be as good as "Thomas plus a lot more" going forward.
Now, if Thomas' hip proves to be an impairment to him or he ages badly and his play drops off signficantly, then maybe that threshold isn't all that high. Maybe Irving just needs to be the same player he has been.
But if Thomas returns to full health and produces at anywhere close to the rates and efficiencies that he has the last couple of years, then Irving simply _has_ to be massively better than the latter has been in his own recent years.
Because it isn't going to be just Thomas' lost productivity that he is measured against. He'll be measured against Thomas plus whatever value the Cavs get from Crowder, Zizic and of course, the BKN18 pick. The latter doesn't even have to be a top 5 pick to have pretty significant value.
Is the trade a bet ON Irving (that he will elevate his game way beyond what it has been)?
Or is it a bet against Thomas (that he will decline significantly)?
It could be this simple.
Kyrie Irving ~= Isaiah Thomas
Kyrie costs $18 million this year, $20 million the next. He'll probably cost $28-30 million for the next 5 years after that.
Irving is making 18.9M this year and 20.1M the next.
Are you asserting that Irving will sign for a below-max contract in 2019? Because a max contract for him will probably start at a base salary of 32M (assuming early projections of a 106M cap). He would then be eligible for 8% Bird-Rights raises each year from their for the 5-years. I think he'll be making quite a bit more than you are estimating.
Isaiah Thomas costs $8 million this year, and probably $30 million for the next 4 years after that.
Thomas costs 6.3M this year. The max contract base for next year will likely be 31M (estimated salary cap of 103M).
Irving would be more expensive in current and accrued cost in every year over the next 6 with the exception of 2018-19, when Thomas would briefly make more than him. In every other year and in total cost, Irving will be more expensive than the maximum Thomas could make during that time. And of course, Thomas may not get a full 5 year Bird Right's contract. I've alway guessed he more likely would get a 4 year deal. Even that is in question now, given CLE's tax situation.
If Ainge thinks Kyrie is going to play at an All-Star level for the next 6 years, while Isaiah will only be at that level for the next 3 years, it's easy to see the math for the value of the trade.
So that becomes a bet on IT's decline. That's a fair position to take. Though it presumes no replacement.
What if you had instead used that Net's pick to take Luka Doncic? Then upon IT's decline, he slides to the bench behind the latter. So many variables in the future, of course.
But to me, to justify the emotional gut-punch aspect of the trade, the bad taste it leaves in the mouth to exchange the guy who was the heart of the team for the sourpuss crossover artist on the team that we hate, Kyrie needs to take his game to another level. He needs to become a James Harden type offensive superstar who can carry a team.
Otherwise all the trade has accomplished is upgrade the team on paper, and extend the window of the core a year or two, while making them significantly less fun to watch and root for.