Martin Luther King, Jr. will always be best known for the campaign against formal racial segregation, but his later speeches on economic justice are very interesting. In a 1967 Southern Christian Leadership Conference presidential address he calls for policies of full employment and a guaranteed minimum income:
The problem indicates that our emphasis must be twofold. We must create full employment or we must create incomes. People must be made consumers by one method or the other. Once they are placed in this position we need to be concerned that the potential of the individual is not wasted. New forms of work that enhance the social good will have to be devised for those for whom traditional jobs are not available. In 1879 Henry George anticipated this state of affairs when he wrote in Progress and Poverty:
The fact is that the work which improves the condition of mankind, the work which extends knowledge and increases power and enriches literature and elevates thought, is not done to secure a living. It is not the work of slaves driven to their tasks either by the task, by the taskmaster, or by animal necessity. It is the work of men who somehow find a form of work that brings a security for its own sake and a state of society where want is abolished.
Work of this sort could be enormously increased, and we are likely to find that the problems of housing and education, instead of preceding the elimination of poverty, will themselves be affected if poverty is first abolished. The poor transformed into purchasers will doa great deal on their own to alter housing decay. Negroes who have a double disability will have a greater effect on discrimination when they have the additional weapon of cash to use in their struggle.
There's a lot of insight here, but I also think it's an interesing example of how things change. Back in 1967 I would say that it was roughly accurate to say that the problem of "affordable housing" was essentially just a sub-set of the "poor people don't have jobs or money" problem. But in the roughly 40 years since 1970 that's really ceased to be the case. Clearly any individual low-income family could drastically improve its housing situation by obtaining more money. But in America's major coastal cities exclusionary zoning practices that hadn't been developed in King's day (people had, at the time, blunter means of keeping out the undesirables) reduce the housing supply regardless of income considerations. If you keep the stock of housing fixed, then higher incomes simply spiral into higher prices. In today's conditions, you have to increase incomes at the bottom end but you also need to increase the supply of scarce commodities—of houses located in safe neighborhoods that offer convenient commutes to job centers—on a separate track.