When you are renting a flat in another town, or country, sometimes weeks or months in advance, the risk is much higher. If upon arrival you discover you have been scammed it has a much higher impact than a delayed meal. This favour a single actor that you can trust (however bad is Airbnb, image what it would like if you had to trust a local actor in a country that you have never been, acting without respecting the regulations…).
This makes the dynamics of those two types of marketplace completely different.