I get they want to keep their talents and jobs. But it's just not viable for the future and it has nothing to do with cost.
The future is RPG games where the NPC's can generate their responses in real time and not in text way, but fully voiced.
There is no pre-loading responses. The future is curated content responding to the player.
So to achieve that, its either a fully generated voice like a vocaloid or you train an AI on someone's voice.
If the voice actors aren't interested in it being their voice, they'll find someone or go vocaloid.
It's not about saving money. It's about pre-recorded voice lines being dead on arrival.
Think audio books, but choose your own adventure audio books, where all the names/places/things can be curated to the listener. Voice Actor isn't going to be apart of that.