It took someone called Ford to spell out the truth. “The business model that sustained us for decades is no longer sufficient to ensure profitability,” said Bill Ford, then still chief executive of the great motor company, in an e-mail to staff last summer.

That was bound to attract the attention of any decent strategy consultant, and it is not surprising to see Chris Zook quoting it in his new book. Zook, head of Bain’s global strategy practice, has completed what is in effect a trilogy of publications on strategic focus.