It's clear that they're going to need to rebuild following 2018. However, they didn't have to mortgage 17-18 to get value for Irving. The east is still weak, and they still have the best player in the league. They have a punchers chance at being the Warriors' sacrificial victim next June. And they still get the Nets' pick, which should be top 5. There are very few such deals for a malcontent in the league's history.
For a different comparison, it blows the Bulls' return in the Jimmy Butler trade out of the freaking water. Butler and Irving are similar players - Butler may be slightly preferable - signed through 19-20, with Irving making a few more dollars. Jae Crowder may end up being a better player than anything Chicago received for Butler, to say nothing of IT and the Nets' pick.