Many people, just to pay their taxes and eat, have to work desperately to make money. How much can they save? Once they get sick or encounter a mishap, they're done for. In such circumstances, there's naturally no extra energy left to "pay attention to hygiene," which is why things can appear dirty and messy.
Although this problem could be solved by building more housing, the safe zones are too small, and most of the land must be reserved for farmland. Therefore, most people's living standards are definitely sacrificed, and they have to move into publicly managed apartment buildings.
Even this is only because the Transcendents are helping with farming. Otherwise, there wouldn't be enough food supply, and conditions would only get worse.
It's only in the central district, a relatively prosperous area, that has entry fees, where everyone's quality naturally improves, and so too does the environment.
So you see, just living in the safe zone isn't really expensive.