[alted]

I do research in a university lab that is also used by a number of companies. People make plenty of transistors, including state-of-the-art research.

However, reasonably sized processors need millions of transistors, and (a) we can't easily make that many at competitive feature sizes, (b) it takes significant time and effort to set up and debug a process, and even more to get high yield. So while it's theoretically possible to make small processors, it's much easier (and, including labor, probably cheaper) to leave that to dedicated fabs. Small prototyping runs (via [1] or similar) are common.

Instead, people use the lab to, e.g., prototype new MEMS devices or test new types of transistors or memory cells. Once the technology is proven, it can be mass-produced elsewhere.

[1] https://www.musesemi.com/