Your questions are stating false comparisons. The only alternative to buying a house you listed is renting an equivalent house. But there are several other alternatives. To buy a house you must qualify on you and your spouse’s/ Co buyers proven income. So even if you intend to have a roommate, you cannot included the rent they’ll pay in your income. But it’s almost trivial for two couples (4 incomes) to rent a house together. There are also apartments, or trailer parks, or living with parents.

But let’s get back to equivalent homes.

A young couple makes 80k/yr and wants to buy a 250k house. They can’t afford much of a down payment and finance 225k. They’re paying roughly 2500/mo in a mortgage tax and insurance. That’s roughly half their take home income.

Older couple makes 160k/yr and just sold their previous home walking away with about 100k in equity. They also add 25k more for the down payment and finance 125k. Now their mortgage is 1200/ mo and they make more money so that represents a far lower percentage of their take home income as well. Even if they still only made 80k the fact they were already in a home with equity still leaves them with far more spending money each month.

The young couple is going to be in an apartment, or a trailer, they’re never getting into that home, even as a rental, unless the owners bought it during a low market and have a low mortgage and are not trying to get “today’s market rates” for it.