Honestly these people sound a bit lazy and entitled, and like they were so focused on simply having an outdoor space they didn't even consider the issues and work that can come with it.

I rent a first floor apt with a small yard. Every year in the spring we spend a weekend cleaning the dead plants and leaves, add some new plants if others didn't take well or grow back. In the summer we make time to water plants daily and pull weeds weekly. We make sure drains aren't clogged to avoid water pooling for mosquitos to breed in, and clear plant debris so it doesn't build up to provide nesting for rats. Yes it's more work but it's really not that crazy, just requires a bit of manual labor.

In the mornings I drink my coffee and watch the various birds (that aren't pigeons!) show up. I've seen a mama raccoon with her babies run by. We have a fig tree and tomato plant that produce fruit every year. We plant herbs loved by caterpillars that turn into lovely butterflies. It can be so cool seeing some nature in the city and maintaining the space is worth it.

Sure there can be issues that are out of your control, like if the neighborhood has a rat or bug issue or the yard was not set up with proper drainage. But it sounds like these people thought their yards would somehow just take care of themselves and they could reap the benefits with no work.