It's funny how none of these companies mention economics.
Sure you can build III-V Gate/Transistors, you still have to package 13 chips in an Iphone. That's were the holistic cost lies.
Maybe a refresher from one of the leading authorities on this subject:
http://www.nist.gov/pml/div683/conference/upload/venkatesan.pdf
ps: He's our CEO and this was done for Global Foundries, they must take this research lightly. GlobalFoundries doesn't seemed to be up to date on current developments in the Si world.