You can't pay janitors enough to deal with degenerates who routinely deliberately destroy public bathrooms in western countries. It's a job for police and the courts, but those are dysfunctional in a way which "more money" doesn't fix.

Result is all the clean and useful bathrooms are private, because only thus can shit-smearing vandals be reasonably excluded (and only then, somewhat.)

So you can't pay a janitor enough to deal with vandals, but somehow the minimum wage bartender that already has to tend to a bar and cash register is able to keep their toilets clean no problem?

It's not that hard to make toilets that are nearly indestructible and can be very efficiently cleaned by a guy in a "hazmat" suit with a pressure washer. It probably wouldn't be that hard to largely automate this. But the market for this is small and mostly governments, so prices are high and innovation is low.