> Prostitutes are paid a lot
That's not a fair generalization. Most sex workers remain in poverty, and it's extremely risky work -- for all that men's rights activists like to talk about men having the most dangerous jobs, their statistics are drawn from a perspective that sex work isn't a "job" -- so the actual #1 most dangerous job, mostly done by women, is overlooked.
Even in places like Canada were the work is decriminilized and clients are criminalized, sex workers rarely go to the police after being attacked or raped because the common response is that the worker "asked for it." Sex workers are freelancers: they don't get insurance or other benefits, so they need to charge a higher rate up-front.
Rather than limit the amount that sex workers get paid, it would be better to legalize it and treat it like any other job. Forced labor (pimps and sex trafficking) is already illegal; those laws just need enforcement, which will be easier with the transparency of legal employment. Also, individual workers and brothels can get insurance, medical and otherwise, hire security, etc. to improve the safety of workers.
Let the free market sort out the price.