If you look at pc games you will find that there are more games for the pc then consoles. A game which came out a long time ago will work on a new pc
(mayby).
If you want to play a game that is to high a spec you can buy a new gfx card or whatever to upgrade your pc. When playstation 3 games came out the only option of upgrading your playstation 2 would be to buy the whole ps3.
The computer can do alot more than a console, and you can get joypads and other gaming controls for it.