Of course. That would be the whole point. In that case the OTAs would need to start figuring out how to actually produce value to both end customers and hotels instead of just rent seeking.
Hotels are of course free to decline a business relationship with the various OTAs and traditional travel agencies for that matter. So long as no one OTA has a monopoly I don't think there is a problem.
But you understand that as the end customer, you end up paying the fees anyway, even if they are not visible in the bill? If your customers were unhappy about the extra cost, maybe you were not open enough about them or maybe the customer did not think your service worth the extra fee? After all, if the end customer is the one paying the fee, hotel has no incentive to try to get the customer past the OTA. They get the same money anyway.
I'm sure you are aware that the entire travel industry, predating the advent of OTA, works on a commission basis.
So long as there is sufficient competition in the industry then I don't think it's in the consumer interest to ban rate parity.