They are experts in iron, and processes, but they still would have a lot to learn, and it is unlikely they could ever do better than TMSC who isn't stupid about manufacturing. Maybe they could find something, but so can the others.
The commitment just to play is very large, it probably isn't worth it. Even if you had proof of this would happen in 2015 and so enough time to build I doubt any would build s fab (though they would buy chips to store)
Wasn't thinking 7nm cutting edge, more along the lines of op amps or maybe a 70's era microcontroller - I had the impression lots of chips are used, and some are real fancy, but some are just old and, since they didn't order them, aren't being made.
I'd thought if someone was willing to roll back the clock 30 or 40 years - that tech might be cheaper and more realistic to bring in house. But yeah, there are already plenty of people that do that well, so it's really just an expensive boondoggle.
Definitely not something you can just put together in a few months.
The commitment just to play is very large, it probably isn't worth it. Even if you had proof of this would happen in 2015 and so enough time to build I doubt any would build s fab (though they would buy chips to store)