The classic “You will own nothing and be happy”
During the period of the mortgage, while rent wouldn't necessarily be cheap, it would be cheaper than the TCO of the house. The overall financial consideration is complex and pro-ownership dogma is just dogma: see e.g. https://www.youtube.com/watch?v=j4H9LL7A-nQ. More importantly in my opinion, though (and especially for single childless people), rental housing is available in smaller and finer-grained quantities.