This reminds me of LMAX, who found the fastest way to build their stock exchange was to make the core logic single-threaded, surrounded by multithreaded I/O:

https://www.martinfowler.com/articles/lmax.html

I believe other (grown-up/legacy!) exchanges work the same way.

I wonder how much of the direction of concurrency research is driven by the fact that there is much more publishable work to be done in managing concurrency rather than avoiding it!