I'm trying to learn, I'm not in the industry, please forgive the noob question.
What is the thing that you must learn in mass production that you cannot learn at small volume, R&D stage? To draw the analogy, is it like a clinical trial where you need huge population/test numbers to find the small problems that hurt yield/performance etc (like the blood clot problem with the Oxford/AZ vaccine, which is ~1 in 1M)? But probably you don't need huge volumes to find a problem that's affecting yield measurably (at say 0.1% level).
Related to that, it is claimed (for example here:
https://stratechery.com/2018/intel-and-the-danger-of-integration/ ) that Intel's fab problems originates from controlling smaller fab market share, which is all getting concentrated to TSMC/Samsung at the leading edge. How much of this is true? I mean, sure, infinite money helps, and you can do crazy things like have multiple teams of engineers work in parallel on the same problem. But isn't most of the money used to build fabs going to setting up the factories, as opposed to paying + equipping a smallish elite team to figure things out?