Earlier quoted context omitted.
Why build more? There's plenty of abandoned/empty housing everywhere in big cities? Unfortunately i don't speak german so i can't give you stats about Berlin, but in Paris alone it's >200 000 empty housing units according to official statistics. Building more is definitely the wrong solution to housing. Just remove the capitalist vampire landlords making a profit on basic human needs, and let everybody enjoy free hou…
https://en.wikipedia.org/wiki/Supply_and_demand
People can't live without housing so demand is not elastic. Plus the housing market is special regarding spatial location. Applying regular market rules as if the housing market behaved the same as, say, the screwdrivers market, does not make sense at all.