I was just thinking about this today, and I wondered how Nolan North and Troy Baker ended up becoming two of the most heard (recognized?) voices in videogames.
I honestly couldn't come up with a good answer. It seemingly just sort of happened. I know they're incredibly talented, but in the last console generation and so far this current one, they have come to dominate voice roles.
They certainly fit well in the generic white guy main character role, and we all know there are a lot of those, but there has to be a better reason why they're everywhere.