Hi Martin - our neighbours have 4 AIRBNBs in our street. That's 4 family homes that could be rented out, but are not. They make a HUGE amount of money for the owners.
Imagine this being replicated world wide and you can see why we have a problem.
In some parts of the world councils are taking steps to curtail this initiative.
The big boys at the head of this business model were ten years ago, poor college boys. In ten years they are collective worth for memory, 100 billion.
None of us has enough life years to ethically make this kind of money.
Here's a link that might give you an idea.