What on Earth are you talking about? So what if a newer game comes along with a few new features? The old games are just as playable now as they always were. I'm going to keep on playing my D/P just like I keep on playing my GenIII games. They'll probably fit into these roles:
Diamond: Chaining, SRing shinies
Pearl: Pokédex → GTS patrolling, EVing and breeding → wi-fi trading
Platinum: VS Recorder → Wi-fi battling
Of course, I have to finish playing through Diamond and Platinum first, and actually raise a competitive team, finally.