Is that not what every company does? At least any company big enough to have HR/some formalized ladder/promotion process? And any company large enough to have teams probably has a leads where a decent chunk of their work is doing that mentoring and figuring out who's ready for what work, or how to break it down into something their team is ready for if needed?

e.g. my current company's ladder explicitly mentions that the first two levels are receiving active mentoring and supervision. Third (~5 yrs xp) is still receiving mentoring but also providing it. Fourth and up you're generally expected to be the one doing the mentoring.

What that actually means on the ground is that I try to make sure my teammates are asking good questions/paying attention to the right things/thinking from the right perspectives. I can also let them know about some solution or basic approach for what they're doing, but then they need to go read more and think more deeply about what I'm talking about. So to me, "skills" are just something people need to pick up themselves.