I average only a few reviews per year, if that (my last one was more than 1 year ago). Yet, I'm pretty busy because I see a lot of regulars. Also, as others have said, many clients don't review.
I do see some reviewers, but not all of them review me. Probably a major reason is that I do not ask them to review me. But, I know that a lot of ladies do ask... some will even discount sessions or offer favors to clients who have reviewed them (so long as they review highly).
Also, I see reviewers as atypical clients. They don't contact me in the same manner that "normal" clients do. For instance, one reviewer who contacted me last year asked me to do an overnight for my 2-hour fee. Who does that??? Amazingly, I was "out of the country" for the entire 2 weeks he was visiting my area. LOL. Also, some who do contact me are heavily blacklisted, or just don't make it through screening for some other reason. Also, a high proportion want shorter incall dates, and that's not something that's feasible for me to offer at this time.
I recently asked one NOT to review me, because he pressed me for some favors that made me pretty damn uneasy... and I was worried that if he DID write a review, he might try to use it as leverage to press for more. I didn't want to be worried that I'd end up with a 2-2 if I refused his requests for subsequent dates (or whatever else he'd ask)