the problem with alot of these assumptions are based on the assumption that the majority of people would be better off under this system than otherwise, that everyone who would be slightly better off would be happy to sacrifice the possiblity of being even better off in the future under the old system, that governments are the best way to allocate any resource.
I can't imagine a housing system run by the state would be anywhere near as good for end users as one run by individual making choices (doing the bulk of the work themselves), landlords, letting agents and banks for the majority of people, the only possible improvement would be lower monthly housing costs for some people, and limited increased security (although arguably, you are less secure if you only have one source of housing). Think about it, only one landlord for everyone - if you have a problem with it, where else will you go? No longer will the individual have any control over their home envirornment.
When we were renting, if my boiler broke, I could contact my landlord directly to get him to fix it or the letting agency. I didn't have to deal with any beaurocracy to get it fixed. If they didnt deal with it in a timeframe I wanted, or pissed me off too much, I had the option of moving to a different landlord/agency with minimum fuss. Before moving in, time frames for repairs could be discussed, and there was variation with different letting agents and different rent levels. If everyone has the same landlord, you have to put up and shut up with problems.
We own now, if the boiler breaks, we arrange to fix it ourselves, we have control over it, we can book when we want someone to come round, we get to pick which repair company we use. Yes we have to pay for it, but the upside that I could easily have 40 years of living rent and mortgage free once the mortgage is paid off makes that worth it compared to renting a similar sized property.
I also have a problem with any society that suggests what I have should be based purely on someone else's decision about my level of 'need' not on my level of 'want' or my ability to pay. Perhaps it's because since leaving uni, I've always lived in places that under council rules would be 'under occupied' - while I could always have coped with smaller properties, when it's been entirely my choice, I've chosen to have less disposable income and more space in more expensive areas. I've worked with woman who've made different choices, lived in much smaller places in rougher areas, then had Jimmy Choo shoes on their feet and prada handbags on their arm with the difference.