There is a temporary work-around, I would think. Presumably the data that games expect to be driving sound comes out in a byte stream, like anything else, expecting to be passed to a side-effect producing function provided by the environment. You wouldn't need to even write the code that processes that data into sound, you could just sample (perhaps on original equipment) and provide sound resource files, and then make sure to play the right sample for any particular set of bytes passed to your implementation. (Even if Web Audio standardizes, it's not clear to me how you would handle essentially arbitrary output-to-be-interpreted-as-sound from an arbitrary process!)