That kinda applies to anywhere in the world. On the average, I've seen much cleaner toilets in first-tier China cities than first-tier US cities.
And much more accessible as well. Free public toilets literally everywhere. All over the city, in every shopping center, in every coffee shop. And you don't need to buy a coffee and trash it to use them.
Free, clean toilets are everywhere in America, just not in the dense city centers (walkable, transit-oriented, mid-rise or higher) that people tend to visit on vacation. I'd estimate only 10-15% of Americans live in these city centers, whereas in China it's probably closer to 50%. With the raw numbers, this difference shouldn't be underestimated.
aka exactly the place people need them regardless of which country
In the boonies it's much more acceptable to go in the bush in either country as well
What are you basing this on? China does not have a "tier" system for its cities, and certainly not one based on "the quality of life for the middle class there".
That definitely tracks. LA has a massive unhoused person issue, many of whom with severe mental disorders. You feel a lot that in the commons, especially as you get near DTLA. New York is shabby and dirty in general. More so than a big city usually is. And it's not really a charming shabbiness from an extreme subtropical climate as you get in Taiwan.
The relationship China has with its tier 1 cities is more similar to other Asian countries, like Japan and Korea, than it is to the US.