I repeat my statement: “All else equal, it is harder for a low-income homebuyer to save enough money for 20% of 3x his gross income. … Mandatory 20% down payment for everyone would push disproportionate numbers of low-income families into rentals and disproportionate numbers of low-income houses into investors’ hands.”
If you don’t have the income, you’re not going to live in a $1M house anyways, whether someone gives you a 3% down or not.
If we go by 3x gross rule, a person with 50k income will live in a 150k house, a person with 200k income will live in a 600k house. The difference being, that the 600k house will be owned by the resident (it’s easy for him to save for the down payment), and the 150k house will be owned by an investor (it’s hard for the resident to save, so he’ll rent instead).