There aren't any mobile GPUs that support cuda-style parallel programming yet. Even if a phone did launch with 4 stream processors/cuda cores it would still need another 1300 cores before it could compete with my desktop graphics card in terms of power.
I think one big reason we're seeing comparable graphics on mobile devices now is that they are just now getting close to the capabilities of the 5 year old console hardware. Most dev studios need to target this old hardware and make their games scale to it.
When the new consoles come out the gulf between mobile and console gaming will again be huge and the consoles will immediately begin to lag behind PC hardware as usual.
Maybe game companies will continue to make an effort to scale their engines to mobile hardware as well but I doubt it as the architecture is fundamentally shifting to make use of massive parallelism.
> Please let me dock my 2013 mobile phone with 4 GB RAM and 4 Kepler-PhysX cores...
Are there any phones currently with Kepler cores in them? A quick search didn't yield any.