Food and shelter are cheaper than at almost any time in human history. Additionally, people have more variety of healthy foods all year long.

No matter how cheap food and shelter are, there will always be people who can not acquire them. Halting all human progress until the last human is fed and sheltered is a recipe for stagnation. Other cultures handle this with strong family bonds - those few who can not acquire food or shelter for whatever reason are generally provided for by their families.

The US has built its physical infrastructure to make familial interdependence extremely difficult and often impossible.

Too monotonous housing mixes over too large of areas.

Large houses make familial interdependence extremely difficult? That doesn't make sense. Or did I misunderstood? I don't live in the US.

Most people don't have houses large enough to house multiple generations inside the house. Houses are sized for parents + kids. And those are the only dwelling units available or legally allowed for vast distances in any direction.

From what I've seen American bedrooms are far larger that the 12 square meter bedrooms that are normal for two or three children to share in my country. Grandparents don't need a separate wing, they need a room.

Cheap depends on how we define the cost. In relative terms, food is more expensive than ever:

https://en.wikipedia.org/wiki/Baumol_effect

Food is not Baumol, productivity increases is how we went from 80% of the population working in primary food production to 1%. These increases have not stopped.