How long until a ps4 level $400 hybrid is possible?

[JRPGfan]

Kerotan said:

I believe Sony will be looking into a ps4 portable in the next few years.
How long is it likely before they could sell a ps4 portable hybrid for around $400?

How much would it currently cost if possible? Any experts in this field I want your thoughts! 

The 2700u is a 15-25w part and it can do 1.66 Tflops of compute performance with its GPU.
its on 14nm.

If they made it run all games at half resolution when as a handheld, and when docked full res. (like a switch) where it can draw like ~25watts,
they could probably make such a device today.