Ok... owning couple of dozen sites all submitted and fully indexed, I have never seen even single URL re-written. Does this really happen?
Combining this rate with the rate seen by the article (rewritten 61% of the time, on the subset of 81,000 URLs they were interested in), I'd guess that some websites see a lot of rewrites and many other websites see none at all.
[0] https://developers.google.com/search/blog/2021/08/update-to-...