@Kelly1511 How is it fair to guests? Guests book properties in large part based on the reviews. The new owner may not be a good host. They may turn out not to properly maintain the property, not be responsive to issues or communicate well with guests. How would it be fair to simply transfer their bookings to the new owner?
You can't sell an Airbnb business, you are only selling the house, which is why you can't just transfer guest bookings. The business is the host, not the property. If the new owner wants to use it as an Airbnb, he is starting a new business.
The only party transferring bookings would really benefit is the buyer, who hasn't proven themselves as a host yet, unless they already have other listings and good reviews. So why should they benefit from bookings made based on another host's ratings and reviews that the previous host earned?
Now if the guests wish to keep their reservation, after being informed of the change of ownership and host, then I agree that Airbnb should facilitate that process for them, so they don't lose the service fees they paid on the original booking. But that should be a process between the guest and Airbnb, not the original host just shifting all the bookings to the new host.