Earlier quoted context omitted.
> High rents are created by high local productivity. Wrong. High rents have many reasons and also good policies to get them down and have affordable housing for more people, also in otherwise expensive and popular cities.
Nope. Rents cannot (at meaningful scale) exceed local productivity, or else there will be widespread vacancies and landlords will reduce their rents. Rents cannot (at meaningful scale) fall below local productivity, or else landlords will simply raise their rents. Go talk to a landlord about how they site prices. Step 1. Look up income of your target demographic Step 2. Eat 30% of their income Can you show me a place…
Now make a law that makes construction cheaper. Or make a law that makes construction more expensive. What happens to rent and mortgages, even though productivity hasn't changed at all?
Productivity (or, rather, wealth) of the occupants is a very strong factor, but it is still just one of multiple factors.