Agreed, they should really be trading for lottery picks and hope to get a guy cheap for 4 years.
In fact, one of the main reasons I think we have done so well compares to the Thunder struggling to keep their players is because Manu and Parker were drafted into a championship team with the MVP, which made it clear that Duncan was the man and asking to be paid the max along with Duncan would be silly, whereas Westbrook and Harden came in before Durant became a superstar and so they consider themselves much closer in value to him, when they aren't.