I am genuinely serious. As a recent example, a company I worked at for most of 2013 was doing a round of hiring while I was there, so I was asked to sit in with the team lead on a number of interviews and I would say only 20-30% of the candidates could actually solve that basic problem correctly. They all had a go, but some looked way too stumped for what should have been a walk in the park, some massively overcomplicated the logic for no obvious reason, and a bunch of them made really stupid errors like forgetting that integers could be negative, and so forth. It was quite shocking, really. Many others could not answer a lot of basic questions assessing their understand of object oriented programming, many, who were applying for a web development role mind you, really only understood how to do what amounted to VB-style drag'n'drop programming (despite what their CV said) and barely knew any CSS or JavaScript. I think the team lead had done a bad job of screening, but it was quite interesting to see how many people were applying for intermediate-level web development work and barely had junior-level understanding of what they were doing.
I think the problem is that many people (a majority, even) enter this field as a "career" choice but don't have any specific passion for it. Some are quite intelligent and have a good work ethic and so still manage to make pretty competent developers over the courses of their careers, but without that genuine passion for it, most just learn on the job and when they leave the office, they immediately stop thinking about anything to do with development. It's just not what they would do if money were no object. In contrast, many (most?) of the people here in these forums have a genuine desire to build, to create, and to understand what they're doing. Coding happens whenever we can find time to do it. The simple fact is, the more time, effort and passion you put into something, the better you're going to get at it, and most people in the industry are not coming from that mindset. That, and people are often just lazy and don't get around to making the time to keep their skills up to date.