So while a PC gamer may have to upgrade her video card in order to play game X, a console gamer face a situation where you have buy another console altogether.
a console's lifespan is longer than a video card though. take the ps2 for insistence, it was released in 2000 and games are still being made for it.
whereas since 2000 i've had one computer, which was upgraded after a time with a newer video card, then later with a new CPU/ motherboard and RAM. then a couple of years later i brought a newer computer, which was later upgraded with a new video card and extra RAM, then another new computer more recently, just to keep up with ever increasing game requirements. now i built all these computers and carried out the upgrades myself, so although i spent a lot of money over the years, its nowhere near have much it would have cost for someone to do the same if they weren't able to do it themselves.
now i'm tired of having to upgrade all the time, so the convenience of a console is more attractive than the benefits of PC gaming. so i'll keep a computer for use of applications & internet access and i wont have to spend anything on it for a long time, and use my PS3 for gaming.