"It was the West Midlands' support that kept Rover alive - the Great British public didn't give a damn," he said. "Rover could have shown people it was selling cars they wanted to buy."
Price cuts of up to 19% were unlikely to reverse slumping sales, which had left market share - at 3.68% last month - "in the danger zone".
Prof Rhys said: "Rover needs to have at least 4.5-5% market share with profitable sales. Management must get the company into sufficiently good order to make it attractive to others."
He believed Rover needed to form a joint venture "within 18 months", and predicted that a partner would take a major financial stake in "three to five years".
Prof Rhys called union demands for improved pay and conditions for workers "moderate" compared to the changes forced on employees under BMW's stewardship.