Those who can't, can't.
A mortgage is forced savings, and that makes all the difference in the world, for a lot of people. It's not as clear cut as "those who can't, can't". Plenty who can, won't, unless they're forced to by a mortgage or mandatory pension contributions.
To the extent these people exist, they are the people who get burned by homeownership the quickest though.
That is a social problem so, because those who can build generational wealth with all that comes with it (health, education, financial stability). Those who can't, don't. And that is a serious problem, IMHO.
Yes, but that's missing an important bit: It is saving for retirement using the money that otherwise would disappear into rent.
If you had the option to live for free somewhere vs. buy a house, it'd be clearly far better to live for free and invest all the money for retirement. But rarely anyone has that option. It is really between spending that money on rent (money is gone) or spending it on a mortgage (build equity).