The problem is, when you build more homes, the price of homes go down.
Great for people that want homes and people who are just joining the workforce. Not great for grandma and her retirement planning.
If you frame your housing policy around anything but building more, then housing is fundamentally zero sum. If it is zero sum, that means those couples with a children are being subsidized at the cost of that 20 year old new grad or people who earn minimum wage without a family. Those people look at their finances or their mental health and make decisions about their future. So if people new to the work force are subsidizing those with children you could be harming their mental health to the point where they don't want children.
Why would any sane person bring children into a world that is almost guaranteed to be worse for their children than it is for them? I wouldn't.
So from a systems thinking point of view, the only cogent housing policy is to build more homes.