The other user probably did understand supply and demand. Consumers being priced out of the housing market can be a market failure. And in this scenario, it is a market failure. For every homeless person living in the street, there are 6 empty homes in the US, but a couple with 2 jobs and a down payment can't get approved for a home loan? Most definitely there is a market failure.
As long as there's land to build on and materials to build with, all creditworthy consumers who wish to buy a house should be able to buy one. (I'm using should in a non-normative sense here.) It may not be spacious, it may not be in the best school district, heck it may be a condo and not a standalone house, but it'll be at a price they can afford.