Actually I think GMs would be happy if they were "extinct." The problem is the opposite, they're ubiquitous but they have no role the way teams are playing now! Just kidding, I know what you meant to say.
This is why I don't understand the frequent posts here proposing deals for centers that aren't versatile enough to play against the good teams. First off, Horford is going to be playing center. What they need is a SF/PF that can defend 3/4/5, rebound a little, and hopefully shoot 3s or at least long 2s so our spacing isn't ruined. Basically, they need a LeBron, Draymond, Kawhi, Anthony Davis, Giannis, or young Millsap type. Yes, I realize the names I just listed are basically some of the most untouchable top players in the league.
We do need a competent traditional center sometimes, mostly for the regular season. However, to invest too much in one is a waste of resources considering he will not be able to get on the court for starter's minutes against a team like the Warriors. I'd rather sign a cheap backup center than pay a veteran market price these days.
So please no more proposals for guys like Jahlil Okafor, Alex Len, Deandre Jordan, Andre Drummond, Greg Monroe, etc. I would include Vucevic but he's actually on a cheap deal for only two years so I'd consider that depending on what we'd have to give up.