RE: 2008 isonic's
I would add to steveC's reasoning the fact that customers' attitude is somewhat induced by manufacturers via the way they communicate. As an instance, ever changing graphics and colours (as opposed to i. e. plain white with logos) induce to make changes noticeable even if reduced to new graphics themselves and accelerate obsolescence. Personally I grew tired of this since long now, and I very much appreciate manufacturers that tend to make little yearly changes if any and that use simple graphics keeping them over time. After all, one point that made me choose my Sonic 95 was the fact that it was a third year slight modification of a board that was on the market from two years already, proving that the design was good.