Growing up in the '80s I have owned (or still own) every console worth having, and now with the 360, PS3 and Wii, sure I can have fun playing Guitar Hero or the likes but that's it. The current generation for me is nothing more than party games, whereas the older consoles are where gameplay is to be found. If I want to play a game just to pass a couple of hours I'll bust out some DJ Hero, but if I want to play a game BECAUSE I WANT TO PLAY A GAME, I find myself going back to the older machines.
This could just be my sentimental 80s child speaking but you just can't beat the feeling of excitement waiting for your C64 to load that damned tape, ever so gently turning the head alignment screw trying to line up those flickering bars on the TV set perfectly, or blowing into your NES carts hoping it will play.
As for whether or not younger people can appreciate old games, it's hard to tell. Personally I just think the attitude towards games has changed. Games have become a means to pass the time, and they are perfect, cheap babysitters. Sure we have the whole esports thing going on but where would that be if it hadn't been for Doom?
Oh well, I'm rambling. Sorry about that.