People who play a lot of computer games tend to eighter bore themself and move to different occupations or branch into game testing, game journalism, game translation and ultimately game development.
But yes, if all what 90% people want is playing computer games, that's what they should do. I just think you're off by an order of magnitude.
The only reason people enjoy things other than computer games is because computer games aren't yet good enough.
An environment created especially for the purpose of making us happy has an inherent advantage over reality. (Btw, don't forget the fact that our creative desires can also be realized in computer games.)
Cut back the welfare state and let natural selection regain her course...
"Internal motivation" is a resultant of complex social forces, rather than some absolute immutable physical law.
Btw "progress in doing things that you really like" takes on a new dimension with people who are "internally motivated" to be rapists, murderers or pedophiles. I know the GP is probably only considering this in the context of "effective parenting", and I apologize for the ad-absurdum, but I don't feel screaming at villains should be made "illegal". Nor everybody's "internal motivation" and "following their passion" universally glorified, as I often hear suggested by neo-hippies.
Of all robberies, murders and rapes only a tiny minority is committed by people feeling deep internal motivation to do so. Most are done by stupid people in a bad situation. Maniacs are pretty rare. Stupid people are a plenty. And they don't dream the life of violence. They have it all right already, some from the birth.
Talking about this tiny minority, I don't see how our yakyaking about following our dreams can affect them. Those people are deeply ill and should see a doctor. I don't see why we should take them into account when talking about how a sane majority of people should live.