There is a list somewhere on forum of all "services" that is agencies that bring you the guests. There are hunderts, biggest one beeing booking.com But they all treat hosts like slave force. That is the way. With this big agencies there are milions of hosts guest can choose from and hosts became easy to replace.
Having a fair trade service and a host friendly agency would be great. I'n mean time focus on really making guests feel special and try on personal recommendations and returning guests.