I've been around long enough to see what a toxic superstar can do. It's really easy to look at the "superstar" and see it as an asset, but forget how much liability to associate with the toxic - and therefore to conclude "net win" when it isn't.

Not saying it could never happen, but it tends to leave your company a prisoner. You can't lose the superstar, but you can't attract other top-level talent because the superstar is toxic, which leaves you even more dependent on the superstar...