Making something accessible for a group of people is an opportunity cost at every step in the process. For some reason you've determined that "making the Java codebase run under wasm" is an acceptable diversion from making it accessible, but what makes other decisions less so? For example, I haven't bothered supporting IE for many years, regardless of the fact that there are potential users that will be unable to use services because of it. Same thing with internationalization, there's an opportunity cost that has to be made. That doesn't mean don't make the decision to expand support, I'm just saying that it IS a decision and it DOES have a cost.

If you don't perceive it that way, you have to accept that there is a near infinite number of accessibility measures to contend with. Maybe I add support for red green color blindness, and then discover there are other types. The package bundle is too large for users in countries with poor internet access, so you need to have a fallback that removes features, and dedicate some resources to minimizing the initial load time. Oh, the input configuration doesn't make sense for users who are unable to use keyboard and mouse, but use an alternative input mechanism, you have to change it to support that. Oh no, adding support to assist those users has made able users switch to the assisted input configuration, and given them a competitive advantage in your game.

Every company cannot service every need. Those that service a need open potential to acquire the market. That may or may not be worth it or possible at any given point, and that's okay.