I'd like a generation to last 5-7 years, but that doesn't mean you should drop the "old" system as soon as something newer comes around. I like how Sony handled the PS2. That's a good example of how it can be done, and NOT like Nintendo misstreated the Wii, droping it like two YEARS before the next system...
I'm on Twitter @DanneSandin!
Furthermore, I think VGChartz should add a "Like"-button.







