6 months is an exaggeration.If you want to be able to play all the newest most graphically advanced games with all gfx maxxed out,you need to upgrade your videocard once a year,if you want to be able to run any existing game with normal graphics and acceptable framerates,you need to do it once in a two years perhaps.CPU and other stuff doesnt affect perfomance as much,so it needs upgrading half as often or something.Without games progress of technology wouldnt stop of course,but would be much slower,and very different.Besides games there are other applications that demand high perfomance,3d-modeling progs like 3DSmax and maya,videoediting tools like Combustion or Premiere,and so on.
