While good game play doesn’t have to be connected to good hardware there’s still a certain level of hardware needed for some of the best games.
Ace attorney on the DS has some great game play and relatively fresh ideas. It pretty much could have worked on anything with more then two colours, lets say and Atari.
Rockstars GTA, or in general the “sandbox genere” simply takes a shed loads of hardware to manage that level of freedom. They pretty much pushed playability and the PS2 to a new level with that game.
Supreme commander has some 100+ units individually simulated, even if you would run the game in 2d mode you still would need some thing around 1Ghz 256mb for just AI. The level of simulation could be abstracted to say units of 10 but for some that’s real difference. Any unit can be combined with new squads, upgraded… that sheer scale just can’t be done on crap hardware in real-time no matter the pushing the boundaries of the platform.
Pushing the hardware for the sake of pushing it, ie demos is another thing. Then you need limits in order to appreciate the pushing, like the amazing 4K and 64K procedural demos of today.