This is a conflation of two thoughts. Firstly, the idea that it's ok to be single, and secondly, the rise of cost in housing so that people are priced out.
In my circle of friends I know single women, who, because they're single are in poor housing. One of my friends even stays with a partner because otherwise she'd be in a grotty houseshare or bedsit.
One of knock-on effects of high housing costs is the effect it has on women, and the difficulty of being independent single women.