Agreed.
I'll put this a different way for those who want to dump him: What could we expect in return if we traded him?
A 1st, or a 2nd round pick? What if the "word" is out and the most Yzerman could get back is a 4th...? My point being: if we're trading him, we're most likely not getting our 1st round pick back. That's a sunk cost. Some might say "something is better than nothing". No, it's not. The worst case is to get "something" back, at a gross devaluation to the 1st, and then another team develops him into an All-Star starting goalie. Or... "Opportunity Cost."
IMO: the Opportunity Cost of losing him is higher than any return we will get for him right now. So I say we either develop him and he becomes a competent goalie for the Wings... or bust. And I'd rather bust than dump him cheaply and then in 3 years he's dominating the NHL, for another team.