It's new around here; until a couple of years ago, I don't remember any paid toilets.

And there are other choices besides "diarrhea floors" and coin payment; in train stations, for example, they could simply charge a fee to the train company to pay for the permanent staff, which could then (very slightly) increase the price of tickets to accommodate it.

If it works it only works by making most of the people avoid them :). I don't expect much from a free toilet but I usually don't have spare coins with me to use (especially abroad) so I end up going to various establishments like McDonald's hoping they don't lock down the toilets. Even if they do, I can buy a cheeseburger for the same price, which buys me both a clean paid toilet and something to eat.