A ~20 year old process... that'd be 250nm or 180nm, which is Just Fine for many microcontrollers, if not the new 600mhz-1ghz Cortex M7's...
Hence never competitive. "It's open!" doesn't make a business decide to buy a million and put them in a product - cost, features, availability, support do.
Nobody cares about "open silicon" - it's only spouted by people who don't understand actual electronics, or if they do, they certainly don't understand the economics.
It will never happen. If it did, it wouldn't be useful. It makes zero sense.
From a state perspective, being reliant on other countries for your electronic may seem like such a threat to your ability to remain sovereign that it's worth developing your own, even if you are generations behind the latest and greatest.
Hell no!