What has changed is that dual income became the norm, and is no longer an advantage, but mandatory to compete on the housing market.
When single income was the norm, the norm was to put a family of 6 in an 800-1200 sq ft residence. That's still roughly equivalently affordable today.
When single income was the norm, the norm was to put a family of 6 in an 800-1200 sq ft residence. That's still roughly equivalently affordable today.