The quality is not an issue. VOD is like putting a slot machine in a gambling addicts home. You have a customer porn addict with their CC # hooked up to the computer and they can order porn after porn after porn until they rub their genitals raw.

Yet, adult content providers choose to provide their content in a form (DVD) where the customer has multiple opportunities to change their mind and come to their senses. If adult companies are losing money, its really no one else's fault but their own. To boot, they could be reaching customers outside the U.S. and building a foreign market.