But even that surely is less useful these days? In the west we're no longer living in a time where most people get married and then start their lives together.

But even that surely is less useful these days? In the west we're no longer living in a time where most people get married and then start their lives together. People often cohabit for years before marriage, and with more women working and earning as well the "hey I've got money and I'm dedicating a chunk to you!" signal isn't so much of a thing.