A reduction of public restrooms didn't stop the worst 10% of society from having public sex, shooting up drugs, or destroying an area with their lack of defacatory etiquette -- did it?

In places where these things were problems with public restrooms, they remain problems without public restrooms.

The 10%'ers are still doing their dastardly things. The remaining 90% of society still has the same messes to clean up (or to willfully ignore).

Nothing has been improved in this process.

You're right about who is causing the damage etc. but the 'commons' does not refer to the people; it refers to the shared resource. So a public park is the commons. And when it gets polluted with plastic rubbish etc. because externalities are not internalized that's a tragedy of the commons.

Ten percent is way too optimistic, I'd say 20% are destroying everything for the majority.

I tried to find a good term for this trend and the best I could do is "defining deviancy down" defined as "the tendency of societies to respond to destructive behaviors by lowering standards for what is permissible."

It's like a behavioral Overton window that grows downwards.

We are experiencing "changing consumer habits"

Homelessness and the post-2008 wave of poverty ruined it. A few people who need to use a public bathroom everyday is fine, but when you have 100x of ppl who are desuetude, on drugs, mentally ill etc. emptying their medications and needles and so on it becomes a public health hazard and overwhelms staff.. better to just shut it down altogether or limit to staff only. .