Why should they give up such aspirations? Surely the problem is lack of supply; fixing the problem by reducing demand is the sort of thing they tried in the USSR and look how that ends up.
Given only 5% of the UK is build on what we need is lots more houses, with a minimum bedroom size, for a single of 9 by 14 feet and a double of 14 feet sq. Then the garden has to be twice the square footage of the entire house (not the footprint, the house across it's floors).
The reason more and more people want more bedrooms is very simple, and its why we bought a 7 bedroom house. I need an office, as I work from home at least two days a week. My wife sees patients in her office. My family live far away and visit often so a bedroom with an en suite where they can leave a small stash of clothes mean they can see the grand kids far easier. Oh yeah and the fact we have worked hard, saved up and bought a house we want.
Jobs a good un.