Earlier quoted context omitted.
HfH typically provides the mortgage with a 0% interest rate also. They are a tremendous program that should be scaled up.
All these programs that subsidize the cost of borrowing merely drive up the price of houses. This is why things like the mortgage interest deduction or zero percent financing are not in the long term interests of home buyers when they are "scaled up", and when they are niche programs they are basically a convoluted form of charity. There is nothing wrong with that, some people like their charities to be convoluted an…
You need at least all three components. I'd suggest wage support (UBI / employer of last resort) being another leg that would help, given the relationship of rents and wages economically (wages tend to or below subsistence, rents to all consumer surplus).
But this seems a damned good start.