Factor in unregistered "professionals", streetwalkers, freelancers, sex club participants, content creators, and porn stars, I don't think it's at all farfetched to say there's nearly 1 million active prostitutes in Japan at any given time. Also consider the churn of new girls going in and old girls going out. Of 64 million females, I think the true numbers would show that a notable percentage of them have had sex for money.
I just don't see how it could have been worse pre-internet.
