Why not just hire a (hopefully) good people manager? It's hard to find good managers, but it's also not entirely likely that your best IC engineer is going to be a good manager naturally either. Whereas you know they're good at what they're doing now.
If they're not going to find a way to be more worthwhile, just don't pay them more. If they find a way to be more worthwhile (teaching, coaching, setting standards, whatever), then pay them more.
If they're not going to find a way to be more worthwhile, just don't pay them more. If they find a way to be more worthwhile (teaching, coaching, setting standards, whatever), then pay them more.