The law of supply and demand is as fundamental as the laws of physics.
If you bring millions more people into a country the cost of affordable housing will go up.
Discussion
Moral of the story is to own real estate?
That's the other scarce asset worth owning. They're not making anymore land. Are you really a citizen of your country if you don't own a piece of it?
Law of supply and demand also dictates the value of a single denomination of a common currency when it's total supply is greatly increased.