This is a common refrain, but is it possible that adults have learned valid paradigms that make using the iPhone as it is today, more difficult?  If you want to design for 5-year-olds and have them retain that forever, I guess it can work, but maybe it&#x27;s a design failure if the people who actually buy your product have a harder time using it.<p>To use another analogy, it&#x27;s somewhat like saying &quot;Well, people literate in a left-to-right language have no problem using it.&quot;  Great, but presumably Apple was aiming for a global audience, so pointing out success stories in some subsections of that audience does not mean they succeeded overall.