His lack of all-round game makes it impossible for him to positively effect the outcome of a game when he isn't scoring.
Once you accept that IT and Kyrie are at least equivalent in productivity, but that Kyrie is 4 years younger than IT, under contract longer and at a more reasonable price, you see why they had to give up more than just IT to get him (that doesn't include the fact that they had to add Crowder just for salary matching). And for the team, that means that the production will not drop that dramatically, even if Kyrie is worse under Stevens and without Lebron.
I swear, it seems like Isaiah is getting older and shorter with every CelticsBlog thread.
Isaiah is 3 years and 38 days older than Kyrie Irving. They are not 4 years apart.
FWIW, they came into the NBA in the same season and they have almost the same number of minutes of wear and tear. Thomas has a little bit more minutes from college, whereas Irving has a little bit more minutes from the playoffs.
Kyrie is under contract control for one more year than Thomas. Whether it is at a "more reasonable price" is debatable. He will cost about 13M more this year and possibly about 10M less in the following year. After that, he will almost certainly cost more.
The trade premium was, indeed for the opportunity to sign Irving long term with a next contract starting at 27, as opposed to Isaiah's which would have started at age 29.
So if we all accept that near term, Irving and Isaiah are roughly equivalent in productivity, then we gave up Jae Crowder, Ante Zizic and the BKN18 pick for the
difference between 2 years of prime Irving and 2 years of just-past prime Thomas.
Whether that will be worth it remains to be seen.