Forgive my ignorance, but if the fab generation ahead was already invented, and (my understanding is) a new fab process requires completely new machinery, what stopped AMDAMD, whoever, from "skipping" a generation to catch up with Intel?
As I understand it, every fab generation requires a bunch of changes and new tricks, but they're generally in different areas of the process - and you need most or all of the tricks learnt in creating the previous generation of fab in order to build the one after that. So you probably don't save all that much time or money by skipping a generation, and in the meantime you're a generation further behind and have nothing competitive to sell.
This is why Intel used to beat out much better processor architectures simply by having enough money to always be at least 1 fab generation ahead.