The problem is simple: in a perfect society we wouldn't increase flat prices simply so a landlord can make even more profit. There is no actual, logical reason why the flat should cost 5x as much, only made up ones that basically say "but I wanna!". There's no actual 5x increase in costs for the landlord, they pocket most of that additional rent.
Living space isn't something you should be able to profit this heavily from in a functioning society, as it's a basic necessity to life. It's alright that nicer flats cost more but nowadays we value huge additional profits to landlords higher than basic human rights, provocatively spoken.