Taking it a step further, what truly defines a PC game or a console game?
You know you're a geek if you start sounding philosophical about the nature of different types of video games.
But really, you made some good points. Consoles really just are computers.
I think the main problem with consoles is their controllers. They constrict the types of games that can be played on the system, and force developers to greatly simply their controls schemes. And this leads sometimes to awkward feeling games, if the developers don't put enough time into cross-platform development - like, for instance, in BiA where there is one button that does like five different things. But worst of all it slightly narrows the kinds of games many developers are able to make, so you get less originality.