Let me give you an exercise in thought so you can see that just simplifying it into "dEmAnD vs SupPly pRobLem" is incredibly misleading.
Imagine there is one person that owns 99% of the worlds wealth. Now, is there demand for housing? You bet. That guy wants to buy all the houses he can. If they build more, he will buy them too. No matter how much supply you offer, the demand will be there. He will buy anything. Now replace wealthy guy by corporations, REITs and wealthy people (who would own not 99% but ~90% of the world's wealth) and entertain me how increasing supply fixes anything.