Those "landlords/property investors" have enough cashflow and collateral to continue to expand their portfolios and get lines of credit to do so, which puts 'normal people' looking for housing at a disadvantage.
In high-demand housing areas, there needs to be more housing regulation to balance the businesses vs. individuals. It's good that there are cool places that encourage visitors to temporarily stay and spend locally, but there are also people wanting to live there that would also spend locally. The property businesses are making such a $/day killing on Airbnbs that they would rather keep that system than rent units for people to live there (and have to adhere to all the landlord laws).
Airbnb is a convenient loophole that offers more money with less effort as long as demand is high.
The principle of supply and demand, or basic economics. If demand for units is satisfied and an agent keeps buying and attempting to rent units, the price will collapse until the agent can no longer afford or buy them.
You may want to spend some time here: https://mru.org/courses/principles-economics-microeconomics
If only there were some way of increasing the number of housing units on a given area of land, this problem could be solved and we could have enough housing for everybody. This kind of technology could really ameliorate such problems.
https://www.vox.com/a/new-economy-future/urban-sprawl-housin...