"You can't force someone to take the time and put in serious effort when someone else is providing a lazier solution that ultimately gets the same job done."
Well, what of the development requirements on PS3 and Xbox 360's multicore processor? Multicore applications are not very easy to program. In fact, I can't think of any multiprocessor games for PC currently. The only things that use it are applications, such as Windows itself. From the rants and complaints of developers right now, it seems coding for the PS3 and XBox 360 are no walks in the park. The PS2 was and is a powerful machine, as some of the games display. However, it was extremely difficult to fully utilize the Emotion Engine, so developers simply didn't. I've saw this first hand, much to my dismay, when I worked at Visual Concept.
A great example of this is EA's Madden 06 for XBox 360. EA themselves thought they could get the 360 to bring movie-like images to life in a game... hence that ill-fated teaser video. Check out the ACTUAL gameplay videos, and it's BARELY an improvement over the Xbox. The animation is just as stiff, the player models and texture mapping are a hundred-fold poorer than in the teaser video. Yes, Gears of War look spectacular, but I haven't seen that game running on XBox 360 hardware yet, so it's hard to pass judgement.
Nonetheless, if it truly is difficult to squeeze marginally improved graphics on the more powerful XBox360 and PS3, I'm sure developers will be openminded to see what Nintendo can offer. If the SDKs are easy to handle, then you might even see better graphics on the Revolution initially while developers try to get a grasp on the intricacies of the PS3 and XBox 360. That alone might give Nintendo the chance to build a larger user base and cull more developers.