The property and land owners in areas like this want to flip everything for the highest possible amount of money. They have no long term interest in it remaining their back yard.

You might argue that it might become self-limiting based on what the market will bear... But looking at London, and the awful living conditions at the bottom end of the market only confirms that once you have critical mass, and people need to live somewhere, vendors and landlords can get away with murder and somebody will still chuck money at them.