On the Smart Phone/tablets side:
Apple seems to be pushing OpenCL, and ARM is behinde OpenCL.
Nvidia's Cuda isnt gonna do much in the mobile phone's.
Tegra2 was "King of the Hill" for like a week, then a competitor had a faster chip.
Smart Phone bussiness is brutal.
Nvidia know what the future of mobile phones might look like though, because yesterdays discrete PC GPU is probably what tomorrows smart phone will look like.
So in that sense they have a tiny advantage.
That said even on desktop pc's, nvidia is generally behinde AMD by a good bit with performance/watt. In a phone performance/watt is probably a huge deal, and Id be lieing if I didnt say I think the competitors in the smart phone bussiness probably are better at makeing gpu's that use little to no power.
On the Desktop PC:
low end GPUs will probably erode to APUs (amd) or IGPs(intel), that are on-die.
High end GPUs will probably erode due to only console ports being made.
Im not sure if I was Nvidia or AMD, Id want to go overboard with chip sizes next gen.
Id go small and wait for next consol refresh cycle, before releaseing bigger chip cards.