Late to the party and all but uhh...
PS2's and PS3's HUGE selling points at the start of their system life was Backward Compatibility. I specifically remember people/magazines/websites talking constantly about playing MGS on PS2 with it's upscaling option. It's the reason I still have 2 FAT ass PS3's in my closet in case I'm feeling nostalgic for PS2 OR PS1 games. I'd wager that you are
mostly right in saying that most people probably want to get a new system for new games, but you are massively underselling the importance of BC. Hell, as primarily a PC gamer, I LOVE getting new hardware and running OLD ass games to see how much a performance increase there is. Not sure why so many console fanboys like to discredit previous generations of software simply because their console of choice can't/won't play the software for arbitrary reasons. I think it's dumb to completely write of 1000's of games across previous generations, considering how some of the biggest franchises ever pretty much ALL started on previous generations hardware. ME is proof positive to that sentiment.