Hi there Higgie! Welcome to the site.
I know we are a good ways away from where we need to be with CC in gaming. But I honestly feel that is one area that is ripe to be jumped on by game developers. I wouldnt be at all surprised if it is the next big area they tackle in making more games accessible. And with a new accessibility rating system in the works - a kin to the current ESRB ratings - I think that will add even more of incentive for them to get with the program. Earning that CC designation on their game will be a feather in their cap for which ever gaming house decides to pursue it.
So many devs have said to us that CC is an easy thing to add. They will certainly increase their user base and make themselves more money if they do it. We are all just going to have to keep pushing for it the way they pushed to get TV CC.