Imagine if the current video game industry was something like "hey, we need to implement pathfinding, call Dijkstra LLC and tell them to licence us their algorithms"... that wouldn't work... I don't see why actors want to be paid perpetually for their job on a game when the actual developers aren't...
Because they look at tv and movies and feel like their participation in game development should be outsized like their contributions in tv and movies.
Ultimately, it comes down to the pie and what is sustainable. Games could cost 100 dollars and maybe there would be more pie to go around or maybe people would just game less.
One thing that has driven the decline in theatergoers is the cost of a movie ticket, but by raising prices, they were able to reinvest in theaters across the country. So there is SOME give and take there.
I think of all participants in game development, voice actors are among the least important, and that isn't to say that they're not important. I'm not advocating that we go back to games without voice acting in many cases, but some of the best games of all time have no mocap and no voice acting.
It's a tough profession though because unlike a programmer for example, you aren't going to be employed year-round. You're almost certainly a contractor/gig worker.