We need to build more housing. Housing affordability would do more to help the middle and lower classes than anything else.
The only way this will happen is for the lower and middle class to realize that they do not need a large house in a affluent suburb with a bass boat, a new RV, two new SUVs, two new cars for your two kids in high school, paying stupid amounts of money and time to put kids through sports, several vacations and four of the newest IPhones, the cellular plans along with every single streaming service.
The above will not happen, so the chances of people actually going out and buying two acres and sticking a mobile home on it are slim.
Affordable housing isn't happening because 95% of the people are fighting over the exact same thing.