ViceVersa has put her finger on the stupidity of the arguments used by those who think the answer to the housing crisis can be solved by older people in bigger homes selling them to families.
The only way to solve the housing crisis is to build more homes. It actually doesn't matter whether those homes are big, small or medium sized, All that matters is that the number of houses in the housing stock euals, broadly, the number of households of all sizes looking for self contained accommodation.
I also do not understand this obsession with bedrooms. A bedroom is a room people sleep in, but too often it is taken to simply mean the upstairs rooms in a house and that is grossly misleading.
Having moved house in the last year I have looked at hundreds of house plans and photos, and time and time again you see upstairs rooms being used for all kinds of purposes that do not include sleeping: gyms, offices, sewing rooms, gaming rooms. Rooms clearly never used for sleeping. We have twice owned houses where one of the bedrooms was a dedicated study/office.
And being always willing to be a devil's advocate, I would ask the question, which group in society spend the largest proportion of their time in their home? The answer is, of course, older people. Single people, families, spend little time in their homes. They are at school, at work, at leisure facilities whether gyms or cafes, out visiting friends and so on.
The older people get, the more time they stay at home. Surely, therefore we are the ones most in need of big houses with large rooms where we can move around, do different things in different rooms, just have space to keep moving and active, even when we are house bound. It is older people who are most likely to fully occupy their homes.