AirBnBs are way more expensive that "traditional" long-term housing. They compete in the same market as Hotels and BnBs, not rentals you would live in for 1+ year.
So yes, they're on the market. A different market than long term rentals.
With the month long discounts they are offering they aren’t that far off from furnished rentals, but with a lot more flexibility.
The legal framework is different, but they all serve people in need of housing in the area.