Not every action has to solve every issue immediately. Things take time. Long term, tenants' unions are ideal, best coupled with legislation to break up these property management companies and private equity firms that have a stranglehold on shelter.

A mass rent strike is an excellent demonstration of people power and a good first step in that kind of long term operation. If you have a better idea on an action that both mobilizes a large number of people and has an immediate impact, you should certainly share it. There are plenty of avenues of attack here.