Yes, he is. But I suspect locking up a star (or potential star) player for multiple years now is a big deal for GMs who don't want to deal with a playing bailing after his contract is up (see Kyrie Irving, LeBron James, possibly Kawhi Leonard, and all the other players who switched teams this FA). Hell, Porzingis got a max deal and he didn't even play last year. And Jamal Murray somehow got a max extension from the Nuggets at >30M per year.
And during the time the player is injured and inactive the salary cap hit is nil?