The reason hoteliers are not offering different rates between OTAs (broad rate parity) is simply because they don't want to risk undercutting themselves. If they offer a rate to one OTA, that's lower than that offered to other OTAs, they still have to offer the same rate as that offered to the OTA with the higher rate (narrow rate parity), making a mockery of the braod rate parity clause which is why no-one takes it up.
The reason hoteliers are not offering different rates between OTAs (broad rate parity) is simply because they don't want to risk undercutting themselves. If they offer a rate to one OTA, that's lower than that offered to other OTAs, they still have to offer the same rate as that offered to the OTA with the higher rate (narrow rate parity), making a mockery of the braod rate parity clause which is why no-one takes it up.