It's been known for years that cost/transistor reached a minima with the move to 28nm and has been rising ever since. Perf/transistor also plateaued around the same time (if not a little earlier) when gate oxide thickness hit the .3nm minimum practical limit (which is why everyone is hitting the same clock rate headroom). The upshot being that if you want more performance, you need more transistors, which means more cost. And that's not going to change without radical changes to how ICs are made, and "new process, now with some EUV!" is not even close to radical enough.