I could be wrong but i think the 560Ti/550Ti/460 is what you find in most pre-built OEM Desktop. which is what most people buy, we are in the minority here.
+1 (no idea what the GPU is in the OEM's machines mostly though).
We are the minority and clearly you can see from Steam that the majority are still rocking older cards. I feel it is great that cards as early as the 4 series are DX12 capable and a massive plus if you still own one.
As for my 8800GT playing DX11 games, yep it does