The thing about monopolies is that the monopolist still has to deal with the demand curve, but they get to set the supply curve. As price goes up, demand goes down; they can't change this. In healthy markets, when supply goes up, prices go down because of competition. Then the price ends up at the intersection of the two curves.
The monopolist doesn't have to follow this rule: they set the price to whatever makes the most profits and leave the price there regardless of fluctuations in housing supply.