There are quite a few levels on Galaxy that effectively look like a "3d-fied" traditional 2d platformer (one of them uses background arrows to indicate direction of gravity....genius).
Super Paper Mario also is a "twist" on a traditional 2D platformer.
New Super Mario Bros is a GREAT 2D incarnation on the DS
VC is there to relive the past, but if you want new incarnations, you can still get them. One of the best cross platform 2D platformers I've played in ages is called
Cave Story (Doukutsu in Japanese)....osx/linux/win/ds/etc
....so they're still being made (albeit in ever smaller numbers).
However Killarapp, I agree with the gist of your thread. I think that, even within Nintendo (the only company left that is still developing this particular genre on both it's platforms) I can see a future where 2D platformers have gone the way of the dodo...similar to how 2D shooters like Space Invaders have.