I have always wondered this myself. Why don't they make games more accessible to everyone? This is one idea I had a long time ago. I thought, if I were to ever start a software company up, I would make sure anyone could use the stuff. We have the technology now to do this, but no one ever does anything. Even all Windows O/S, has very limited support. It's amazing, 2005, yet all software written for normal people. There is only one software company I know of that specializes in games for the blind and hearing impaired.
http://www.bscgames.com/
P.S.
I also think all games should be written with a variable speed control. Then people could slow down the software, so they can manage it. When I am 60 or 70, I may still want to play some games. But I'm afraid I won't have the reflexes anymore for most.