Don't forget AirBnB which has helped take a significant amount of housing stock off the market: https://comptroller.nyc.gov/reports/the-impact-of-airbnb-on-...
When i Moved to the US AirBnb was my best option to get a 2 week home while I hunted for where I would lease for 12 months. A hotel would have easily cost me double because i got a good week or 2 week rate (i forget which) .
America has a massive zoning issue that is causing all kinds of pain and suffering to lower middle class and below.
That's on the market!
So yes, they're on the market. A different market than long term rentals.