Not sure what Median Mortgage payment tells you without looking at health insurance payment, retirement savings, college saving for kids, college debt, auto payments etc.
I would expect a median family with median mortgage to have little money left over if they have children.
https://www.reuters.com/article/us-usa-economy-census-idUSKB...
Median mortgage payment is $1550/mo. 40% of US homes are free of mortgage.
https://www.businessinsider.com/personal-finance/average-mor...
https://www.forbes.com/sites/brendarichardson/2019/07/26/nea...
There are a lot of folks in the US that are just scraping by.
There are a lot more folks with enough disposable income to pursue one of these strategies. Not everybody.
[And this doesn’t include wealth and savings.]