While no one here has any concrete statistics, clearly, I'd estimate that you *are* in the minority.
The book/music comparison is a weak one, because those don't take up much space, and themselves aren't media platforms, they're media itself.
A more apt comparison would be a music player, like an ipod. Generally, when a new ipod comes out, it can play all your old songs. You don't need to switch to your old ipod just to hear the songs you bought last year. It's the same concept. why should we have to clutter our TVs with all these plastic boxes to play old software? I only have so much shelf space, and I'll be damned if I have to wrench out my tv to rearrange wires every time I want to play Little Big Planet. I can probably deal with it this generation, but if the trend continues I won't be able to for the next.
It's a principal of convenience, something Sony's development team seems to have deemed not worth the cost, around the PS3's 2nd iteration.