What Peter Doyle argued (he died in 2003) was that marketing was not a mature and highly developed discipline like financing or economics. It was, he said, excessively focused on branding and it lacked any real insights beyond that. Doyle argued that marketing needed to focus, like all other parts of a large firm today, on creating value for stockholders.
Doyle argued that today's executives are judged solely on whether they increase the firm's value as expressed in stock prices. He argued that marketing had yet to find a way to firmly and clearly contribute to that value. He said that marketing focused obsessively on maintaining the status and image of the firm's brand. However, it was clear to Doyle that this strategy did not necessarily work. He argued that famous brands were prone to lose their value and firms without well-established brands could do quite well.
Because of this, Doyle argued that firms need marketing to focus less on brands and more on actually creating value. If marketers can prove that brands are a reliable way to create value, they will prove their worth. Otherwise, they will face an uncertain future because it will be unclear that their profession is actually useful to a firm.