When I was young my outgoings were mainly the cheapest rent I could find. And maybe a slice of avocado toast once a week /s

This is because rents rise to the amount someone is willing to pay, which is basically what they earn, because they have to live somewhere near work. If they get free board then they can swiftly build up savings and buy a house and continue the cycle of wealth. If they have to pay, they're screwed.