HUD senior sliding scale housing has NOTHING to do with Section 8 and private landlords.
They are buildings typically administered by churches (but open to all religions or no religion) that comply with all HUD rules for the program.
They tend to be well kept up and not slums.
They supply such a tiny percentage of total U.S. housing that it's not credible that they have any impact on the larger private market.
Any lower wealth senior already in the US who is renting, I would suggest researching this and if you find a good one, get on the waiting list.
I will add that the eligibility for the above is about INCOME not savings. They do not demand low assets at all. In fact application evaluators are interested to hear that applicants have significant savings because they know that such applicants are much more likely to be successful long term tenants. In other words if you have a low income and paying sliding scale you don't have much money for everything else so may even default on low rent, so having a reserve is highly desirable.
Section 8 options tend to be slummy and also as mentioned before numerous times there is a definite trend now for Section 8 private landlords to get rid of their Section 8 tenants to be able to ride the gravy train of obscenely inflated rents on the regular market.