I get the feeling alot of the youngsters today are feeling quite jaundiced what with student loans and not being able to buy, in other words I doubt shes cares too much and shes single too which doesnt help. Maybe she'll buck up a bit in a few years timeBut how will she pay the rent when she retires and her income probably drops by 50% or more? Won't be any decent pensions for her and by then the population will definitely have risen by millions. Predictably house building will be a fraction of demand and the demand for rentals will be huge.
She hasn't thought this through.
Just to follow through on your point about demand for rentals, we are now seeing major companies entering the build to rent scene and providing modern, clean rentals with facilities as opposed to some many privately owned overpriced fleapits so maybe this is the way for the future. But personally I would rather my kids bought. It can provide security for their future and gives them a sense of ownership - all healthy stuff IMO.