Frankly, even on its surface, this argument of "CIO as business leader" doesn't make sense. Marketing, for example, is undergoing radical transformation as it shifts to online and digital. Today sophisticated analysis of click patterns, A/B testing, big data analytics and so on are a core marketing competence. Do you think that CEOs want a head of marketing who doesn't know the details of how these kind of marketing tools operate? That marketing is run by someone who can use the language of business, even though he or she doesn't really understand the details of what is done in the marketing programs? Of course not.
IT, too, is becoming increasingly complex. Ten years ago, a company's website was primarily a display application designed to deliver static content. Today, a website is a transaction and collaboration application that supports far higher workloads. Websites commonly integrate external services that deliver content or data that is mixed with a company's own data to present a customized view to individual users. The application may expose APIs to allow other organizations to integrate it with their applications, and those same APIs may be used to support a mobile website. Finally, the site probably experiences high variability of load throughout the year as seasonal events or specific business initiatives drive large volumes of traffic.
Application performance management depends on an exquisite tuning of a multitude of elements, any of which can affect response time and each of which must be monitored to assess an app's ongoing health. To be sure, one can expect the application to constantly change as new business arrangements, partnerships, or corporate events such as mergers or acquisitions require functionality changes.
The complexities of these applications is of an order of magnitude higher than those of a decade ago. For a discussion of what these applications look like from an enterprise architecture perspective, read this post by friend and colleague James Urquhart and just try to come away thinking that this highly complex, dynamic, constantly evolving environment can be managed by someone without technology chops.
You Can't Discuss Tech Without Knowing Tech