My opinion on this is that there are just some games that are easier to play on consoles than on PCs, and vice-versa.
You really don't want to pound keys on a keyboard to play a fighting game, and you really don't want to do the same with two people at the same time on the same keyboard.
A lot of PC users don't have game pads hooked up to their systems, and if they do, it's usually just one instead of two. For those that do have two game pads, they're probably still watching the action on a small monitor instead of a big TV.
Consoles are a natural place for fighting games. Most people buy an extra controller for their systems and play on a big TV.