The blue collar middle class of the middle century was led by industrial scale manufacturing, which doesn't typically come from small companies. I know supply

The blue collar middle class of the middle century was led by industrial scale manufacturing, which doesn't typically come from small companies. I know supply side restriction constrains the creation of new housing as well, but the wealthy buying up properties in cities and renting them out or leaving them unoccupied restricts access to property in areas where land for new building is limited. You can build suburbs all day out in the stix (theoretically) but nobody who works in a city wants a 2 hour commute each way. Depends on the city of course; I'm thinking Toronto, New York and London where empty houses are a big problem but I know that SF has a major issue with NIMBYism so YMMV.