The properties become dilapidated cuz the landlords won’t fix them, cause the rents are low, tenants don’t pay the rent, tenants don’t care about the property and don’t report problems till major work needs to be done, tenants keep their habitation filthy, tenants sublet without owner knowledge, tenants do lots of illegal stuff on property...tenants lie about their reasons for not having rent money,,,,also, most likely property values in the area are low..
No owner is gonna give 3 star accomodations when the renters are slobs. More concerned about keeping the plumbing working, heaters, ventilation, windows, doors, electrical, smoke alarms, gas working and up to date...
You explained it well.