Anyone who's anything-er than you can be your teacher in that thing, if you approach them that way — even if only in your own mind.
If you bring envy to your interactions with these people, the things you'll tend to notice are those that trip envy. If you engage with them as people from whom you can learn something, the things you'll more often observe are just that: things you could learn. They may even be the very same thing; the intent you bring can color your experience of them that deeply.
If you bring envy to your interactions with these people, the things you'll tend to notice are those that trip envy. If you engage with them as people from whom you can learn something, the things you'll more often observe are just that: things you could learn. They may even be the very same thing; the intent you bring can color your experience of them that deeply.