The issue with trading for an MVP-level player is that most often you're left with nothing and it becomes somewhat of a lateral move.
Spurs could trade for Giannis, but then we'd have very few picks left and would have to rebuild the entire supporting cast.
OKC can just offer Williams+salary+6 FRPs and they'd be the best team in the league without even needing to bring in anyone else.
No other team can do it.
Anyhow, I don't think Giannis gets traded before the next summer, who knows what might happen by then.