The two can't be separated at birth. Design is an iterative process that requires feedback loops with the manufacturing teams (including testing and packaging, which may or may not be a part of the fab).
Just an example, the design has to be altered to maximize yields. You don't know what the yields are like or what to alter in the design until you make a few chips and test them, which means you need to design the test harnesses, tape out a prototype, and get both to where they need to be. And then try again.
If the testing, fab, and design people/materials are in different places you have to move things and people around as a part of the process.
It's just an expensive endeavor that's difficult conceptually and logistically, with a lot of institutional knowledge required.
I'm not necessary agreeing with that. Chip fab, jet engine fab, etc. are all at the limits of what Capitalism can handle, as the geopolitics, protectionism, and cronyism attests. The solution is less than clear:
- Because of the enormous costs of duplicated effort. I'm not sure anti-trust will work.
- Nationalist duplication might, but I am not sure whether it will hinder or hasten WWIII.
- Radical IP disembargo with institutional cross pollination works better for codified then opaque-institutional knowledge.
What is nice about vertical disintegration is is forces the the institutional knowledge to by codified. So maybe things can work in tandem, too.
Just an example, the design has to be altered to maximize yields. You don't know what the yields are like or what to alter in the design until you make a few chips and test them, which means you need to design the test harnesses, tape out a prototype, and get both to where they need to be. And then try again.
If the testing, fab, and design people/materials are in different places you have to move things and people around as a part of the process.
It's just an expensive endeavor that's difficult conceptually and logistically, with a lot of institutional knowledge required.