100 years ago the population of the world was about 2 billion. Now it's about 6 billion. Rather than losing land, we gained people, but the effect is the same - 2/3 of the world's population have effectively been made 'homeless'.
I truly wonder about your ability to think logically.
This population growth will most likely continue
AND at the same time, the most habitable land will be disappearing.
There will be billions of new population
AND at the same time, there will be billions of people from low lying areas,...
ALL looking for new accommodation.
It is true, that the problem with past population growth was (marginally) handled by the development of megacities.
But, you use this fact, to claim that the housing problem that will be caused by the destruction of many of these megacities AND the usual population growth, together, will be minimal.
That is truly an example of faulty logic.
You do see how stupid that implication is,... don't you?