> either choke off the young trying to buy or crack the nest egg of the old

The simple fact is, housing can either be affordable xor an investment[0].

Affordable means the prices are flat relative to inflation, which makes it a terrible investment. If it's a good investment, that means the price is going up faster than inflation, which quickly makes it unaffordable.

[0] I want to be clear that I'm referring to housing as an investment to mean buying a house purely for profit purposes, ie, to flip or to rent out. Buying a house to live in, rather than renting the house you live in, can be considered an "investment", but I mean to explicitly exclude that usage of "investment" in this comment.