>> maybe the cost/average income ratio was lower

There’s no maybe about it. In the 70s, average house sale price was 4x the average salary. Today it’s 8x.

How many lattes would you need to have skipped to have bought two homes at the time you bought your first? How many holidays would you have needed to skip to pay two mortgages while you were paying one?

That is the scenario - well except todays generation would only have one house at the end of the day, not two.