Product Management

I've seen in a lot of larger organizations where certain individuals maybe have been there a long time, excuse me, and they understand the business to your point. I could take this person who is maybe a buyer and move them over into a product management role or something like that. So when you build product management teams, how much weight do you put on an internal candidate versus an extra? Does it matter at all? It depends if that person can still serve functionally in that role.