And, really, having a single family home in, say, the middle of new york city IS a marker of wealth. You're displacing however many people could live there if there were apartments.
Many people living in New York rent, with no ability to afford a down payment to own. The maker of wealth is not them.
Specifically, a single-family home has no shared property but is built on its own parcel of land. Additionally it can have no common-walls.
So townhomes and apartments do not count.
This is also called a detached-home in some places.
And based on the context from the earlier post, I'm pretty sure what they meant, but if jfghi comes back and clarifies, I'll withdraw my statement. I don't think anyone thinks renting an apartment is bourgeoisie. However, renting a detached-home in the middle of Manhattan would definitely qualify.
Edit, including a source from realtor.com about their definition:
https://www.realtor.com/advice/buy/what-is-a-single-family-h...