Revenue Management should offer "the right product to the right customer at the right time for the right price" (Robert Cross, 1997). 
Sustainable Revenue Management should meet the ADR, Occupancy and RevPAR needs of current revenue managers without sacrificing the ROI goals of future owners and managers.

The Right Customers
If new customers are always available then long-term relationships may not be important to revenue managers.

On the other hand, if you believe Peter Drucker (1954) “There is only one valid definition of business purpose: to create a customer

Huyton and Thomas (2000) claimed that revenue management "places the needs of the customer secondary to those of the hotel." Advanced data collection systems, sophisticated revenue analytics, computerized management systems and investor demands have diverted a large share of management attention away from long-term goals toward short-term objectives. It is our belief that ultimate success in revenue management will require renewed attention to customer needs.

Tim Tyrrell