When people retire and have very little to do with their time, can't move around a lot but still want to socialise, the internet can help fill that need. And what better way to use it than designing videogames for grandpa? Think about it. They probably won't want to or won't be able to handle the same twitch-spasm FPS titles that appeal to the core demographic of 14-year-old boys, but their brains could use the workout other games have to offer. Something designed specifically to appeal to the elderly, without being insultingly simple or too similar to overwrought "educational" titles, should do really well. And how do you keep those 14-year-olds from coming in and beating everyone, ruining it all? For the most part, they'll be too busy in their own games, injecting caffeine directly into their hearts to shave milliseconds off their reaction times, all to earn the right to call each other names. Games written for the elderly simply won't appeal to them, either because they're boring or because they won't be competitive enough.
Mokalus of Borg
PS - I would love to see games where the elderly simply out-perform the young.
PPS - That would be pretty satisfying for everyone.