No love for Wario Shake? Mirror's Edge 2D? N+?
There are still platforming games, it's just the "catch-all" game play just isn't as wanted as it used to be due to all those other games doing well in their genres. Due to that, due to big platformers not selling as well as they used to, we get far less clones and "me-toos" as we did in the 8-bit through the 32-bit days.
Now, we get platforming aspects in other games instead. Assassin's Creed, inFamous, Portal, and quite a few others just now use platforming as part of the new catch-all games, Sandbox.
I love good platforming, and I'll buy most every decent 2D one out there, but these days they just don't capture the same feel or want by people when they could get a strong FPS or strong Action Adventure or strong Stealth game or what have you. That and some people simply just don't have the time for collect-a-thongs as they once did or wish to spend the time learning so much memorisation just for single player.
Platformers aren't dead, they just aren't the big gaming type they once were. We still get plenty of great games from Nintendo, SEGA has Dimps make a few from time to time, old classics come back, indie and freeware are going strong, and sandboxes take more then a few thoughts from 3D platformers.
Much like Metroidvania games, I don't see it as "they are dead", just "it's niche and get far more thought into making by people who love them".