[ChrisSD]

I could be wrong but it sounds like Bethesda don't own rights to the voice acting. They only licensed it for the purpose of FO3. Outside of that they can't grant or deny anyone permission to use it. Presumably there is either another corporation who owns the VA rights or the individual artists own the rights. There were some big names involved so I'm not sure if that makes a difference.

[datagram]

Yeah, I suspect this is the case as well. As an example, Skullgirls had Japanese audio recorded for its Japanese physical release, but then had to reach some sort of agreement (and probably pay money?) to relicense the voice acting so they could distribute it in the US and through Steam.