It depends.

If the game is already cast and VO/performance hasn't been entirely recorded yet, then yes, it will grind production to a halt.

If the game hasn't been cast yet, some studios might decide to go record VO in the UK instead. Typically that leads to lower quality unless the cast needs to be British. The American voice actor pool in the UK is much smaller than the U.S. for obvious reasons, and that leads to much lower quality of performance.

So basically, it will slow down productions if they don't have the option to go to the UK instead. For everything else, it depends how badly a studio wants to release within the given time frame, but there are options.

No. Not unless devs unionize. More time to make the game doesn't mean less crunch, it'll usually mean more crunch as crunch used to be a month or so before release and is now just the entire time a game is in production. So a longer production just means more crunch.

Crunch is a worker power problem, it's companies taking advantage of the power they have over workers who can't individually refuse.