I think of buying a videogame as most comparable to buying a season of a TV show in a DVD box set: both are ~10-20 hour experiences to have on your TV set at home. The price of a videogame is basically on par in that comparison:

Video game = $50 / 20 hours = $2.50/hour

A season of The Wire = $30 / 13 hours = $2.25/hour