I certainly agree with you, a PC does have many more uses. However when I go to purchase, lets say a toaster, I'm going to pick out a toaster based on its toasting merits and not on whether it can also function as a blender and coffee grinder.
Likewise, if I want to play a game and I have a choice between PC or console, I'm going to usually go with the console option. I know I'm only spending a few hundred to be completely up and running, I know my game is going to work, my hardware is specifically made to run my games and I most likely won't have to patch anything. These points are worth a lot to me as I hate having to worry about system incompatibility issues for reason(s) 1, 2, 3 etc. and wondering if I need to upgrade every few months so I can run game X when it comes out next November.
At the same time, PC gaming is needed to drive forward the bleeding edge of hardware and software developments and there certainly are games that just play better with a mouse and keyboard. There's also the whole modding community to take into account which is definitely worth something. We're going to start to see a lot more mod functionality in the next batch of consoles though, so that major plus for pc gaming is waning.