You're describing the cause, above commenter is describing the effect. Because mental health was basically erased from the government's list of services, a lot of people who would end up there now don't get any kind of help until they're in deep shit and get arrested.

Not that most prisons actually do anything to make sure prisoners are in a more mentally or emotionally stable position when they're released, but practically that's where the buck gets passed to right now.

Probably also has to do with water content. Cats don't have a strong instinct to drink water, and one recovering from surgery would likely be more hesitant to make a trip to the water bowl. Wet food helps cats stay hydrated better which provides a broad range of benefits.