Although there is hope that EUV will help control design rules, the current expectation for developing a 10nm design is in the $200M range. It's expected to double at 7nm and again at 5nm. Try amortizing that over anything but an iPhone, Samsung, or PC volumes.
I'm just arguing that lacking an alternative to silicon transistors, we'll hit limits in die stacking and architecture optimizations that will make < 3nm lucrative for some applications.
