Things I wish existed: apartment buildings with a “mandatory savings clause.” Add in whatever is needed to make it palatable, but fundamentally make people contribute to a savings account each month an amount equal to their rent (increase or decrease by factors required), and that savings account can’t be withdrawn from such that it would fall below amount per month * min(months stayed, 24) before the person retires or leaves the apartment building.
Why on earth would this be a good idea? Wealthy people may be assholes in many ways, but they aren’t going to be obviously dealing drugs in the corridors, they will be more considerate about loud music and parties, and they generally prefer being around other wealthy people for this and other reasons. Traditionally, we’ve kept poor people out of places by actually charging them money, but this results in low savings, insecurity, and much more being spent on wasteful housing than needs to be spent. This method allows for individuals to live cheaply without having to suffer the injury of dealing with low-income people