My slant is that the phenomenon of programmers not reading books could in some cases be a symptom of a deeper shortcoming: the illusion that busyness is equivalent to worthwhile accomplishment. This mentality is exemplified by mottos like "just do it [write code]" and "you're paid to do your job, not think". Its primary activity is scouring the Internet for example code to copy. To the extent it has an associated training regimen, the training happens at the same time as the work happens or perhaps after-the-fact. Its top goal is to produce more lines of code, not to aid the users. It has no inherent notion of a systemic approach to performance, security, exception-handling, and logging. Its style of thought is nonlinear and incoherent, i.e., absorbing ideas that may be excellent individually but nevertheless lack context and organization. Its medium of choice is the Internet (or as the old book Amusing Ourselves to Death alleges, TV). It not merely prefers prose that is broken up into little chunks, it actively rejects prose that isn't. It admittedly excels at the tasks of searching, skimming, and filtering data, yet such tasks are external to the notion that programming should proceed logically.
On the other hand, someone shouldn't respond by slipping into a false dilemma here. The Internet is a fantastic resource for programmers, especially on Web-related topics; programmers who don't cultivate a collection of browser bookmarks are missing out, as are those who don't communicate with the rest. The Internet is an excellent way to keep one's knowledge current, although it's naive to assume that Web trends are necessarily indicative of actual software development trends, which shift direction slowly like a huge ship. The narrow focus that typifies the Internet complements the comprehensive context that a book provides. And the distinction between the two can be murky. I've read online tutorials that are effectively unprinted books (or true unprinted books like Dive Into Python), and I've used some "quick-reference" books whose entries are so terse that I had to supplement the information with an Internet lookup.
Programmers should have the patience (prudence, really) to learn and ponder the entirety and meaning what they do. They should be mindful. Good books aid in that. The work of programmers shouldn't fit the metaphor for life from Macbeth:
Life's but a walking shadow, a poor player
That struts and frets his hour upon the stage
And then is heard no more: it is a tale
Told by an idiot, full of sound and fury,