@Harrison Jones One of the major flaws in your perspective is that it is focused on cheap rent (driving rents down) not affordable housing. These are two different things. Affordable housing in not built by driving rents down, that probably will result in a slum like environment. Affordable housing is about the housing itself and the economic environment it is created in. I believe if people make money and there is sufficient housing supply, housing will become affordable.
You could start a PM company that handles subsidized housing program recipients primarily but I am not sure of the economics of that as it is not my specialty. I am not sure there would be enough margin in this to support your goal.
We know people are not lining up to accept section 8 so you could build housing targeting that group in some locations. You could build or flip less expensive units and sell them to your clients/occupants over time. However, the group you get money to do that from is either government grants or targeted charities because it isn't investors. You are trying to say you will use the " investors" to fund community programs, that sounds like a charity because there is no earning on the investment.
I think if the end result is affordable housing people need to be invested in their own housing otherwise a good percentage of the beneficiaries of your program won't care.