Instead of demanding rent control or rent subsidies it would be more effective to demand a land reform and a land value tax. Georgism is one of those things that has had a long history of success. However, just like the end of Feudalism it is one of those things that can only be acquired by spilling blood as it is extremely unlikely to make the transition during peaceful times.

The "weak men cause problems which leads to strong men who solve them" meme is a good illustration of this problem. During peace there is no urgency, people aren't willing to step over certain hard lines that would be beneficial for everyone but are considered a social taboo over the short term. Some maliciously hedonistic individuals think they can sacrifice some benefits to society for personal gain by staying within the hard lines and abusing "oversights" or "loopholes" that the law set. Until people are starting to burst out in anger and start a "revolution" that would be completely unnecessary if people in power just agreed to adopt the peaceful solution immediately. It's not like Georgism is going to eat the rich, instead it upgrades the capitalists into a more respectable "class" as they can no longer be blamed for this type of exploitation. Let socialists and marxists become an extinct species as they have less and less to complain about.

The loophole is the fact that we as a society have decided that we don't have to share our land with new arrivals (migrants and newborns) and that the cost of public infrastructure should not be passed onto the beneficiaries of that infrastructure.