Computers HAVE to be constantly updated. Both hardware, and software. Any updating on a console, takes minutes at most, and is free. You buy a console once, and it's a small lump sum. In many cases, the consoles costs nearly as much (or less) than the new processor or graphics card required for a game.
Yeah, that worked really well for Sony.
The problem that you are overlooking is that the hardware in a gaming system (say, the PS3) is outdated almost the exact same year it is released. That isn't all that bad; the games for the system are usually made with that system in mind, so they still run fine, even if the game is released years after the consol. However, if an individual is concerned about the hardware, then the consol is almost eternally hopelessly out of date. If you care about the processor or graphics card, then you will ALWAYS do better with a PC, because the PC can always have the most up to date hardware (and thus the most up to date performance, thus allowing for games to continue excelling). If, however, you care about ease of use or sociability, then that is where consol's shine (and curiously, the easiest to use consol does not cost less than its parts).
PCs have the advantages of downloadable content, the potential for constantly up to date hardware, and a more complex user interface.
Consols have the advantages of ease of use, a social environment, and gaurenteed playability. Additionally, certain consols are making headway in user interface. Not by making it more complex, but more intuitive (aka, motion sensitive controls and touch screen interfaces). Answering the same problem but in a radically different manner.
Of course, different types of games work better in different environments as well. Maxis games never seem to translate well to the consol (SimCity, The Sims, and now it looks like Spore as well), for example. Conversely, I've never seem a platformer that worked better on a PC than it did on the consol.
