If housing is an investment vehicle for growing your money, then the people who can participate in that system will work to produce outcomes that fundamentally go against affordable housing. A society that believes in affordable housing as a right or a goal can't allow housing to be used as a place to park wealth so that it grows akin to a stock.
Whatever prices are, they are higher when a landlord is involved. We must get progressively outlaw multiple pieces of land. Owning more than two homes/flats should cost the owner something every year, not generate wealth - and that second one should be nearly neutral.
Until I trust my government to not go hard right, until I can own my housing wherever I want to live in a given decade, until work goes/stays full remote and/or reduces total working hours, until I feel like I have too much money that I could lose the cost of a child and not risk being in the danger zone - until then kids aren't something I can guarantee a good life and that's not an acceptable starting place for me.