I just wholeheartedly disagree that his age should have anything to do with it because he isn't old, has still been improving and the team should expect to still be getting excellent value out of Vucevic even in his last year.
Age doesn't need to be an overriding factor to say no to Vucevic to still be an important factor and even the tipping one.
I think Vucevic has become a good player (after his defensive improvement over the last 2-3 seasons and the offensive improvement last season).
I wouldn't sign him for a max contract or close though.
If he were 25 or 26, I would.
But he'll play next season as a 29 years old and the downside is too large. The risk of debilitating injuries and decline is much larger for players older than 30.
If Vucevic was 26, the possibility of last season being his career year would be negligible.
But he's 28 and 3/4s, so that possibility is pretty high.
And he isn't good enough to withstand decline. All it'd take would be h is game to decline to his 2017/2018 level and he'll become an albatross.
Not worth the risk, especially considering signing Vucevic won't open any sort of championship window.