That’s surprising considering that there isn’t a Google Flights interface for hotels (I.e. an aggregator through which users can purchase hotel reservations through hotel providers directly)
It‘a roomkey.com , but Marriott/IHG/Hilton/Hyatt/Choice/Wyndham franchise most hotels and collect a 10% to 15% royalty of gross revenue from hotel owners, so they don’t care about commissions paid since it’s not coming out of their pocket.