[zacherates]

Isn't that because normal people are heavily encouraged to put all their money into buying a house? Culturally ("rent is just throwing money away" / "the stock market is a casino"), with financial incentives (mortgage interest deduction, SALT deduction, Fannie/Freddy insured 30 year mortgages), and quality of life (school districting/social services or lack thereof), we get people to put every dollar they can into buying a house. Or more than one (apparently everyone aspires to be an amateur landlord). Consequently, you need to have a lot of money before you've bought enough house to move onto buying stocks.

If renting and investing were more normalized and encouraged, I'd expect a different ratio of real estate : financial asset ownership.