The CEOs who presided over the Wintel era are disappearing one by one, and as they look back on their careers, most have the same regret ‘ the failure to spot the accelerating shift from PCs to mobile devices until others had seized the initiative. We heard it from Paul Otellini when he departed Intel last year, lamenting that he had ‘passed’ on an iPhone chip deal; successive HP CEOs, failing to find a new device to take its PC leadership forward; and now, of course, from the outgoing Microsoft head, Steve Ballmer. Ballmer, however, has not talked much about the shortcomings of Windows Mobile and other post-PC efforts. We may think his big mistake was to cling to the…