For example, I once reviewed 8 introductory IT textbooks intended for use in MBA and CA programs to find 3 mentions of Solaris in a cumulative 4,031 pages - and two of those were simply wrong.
In fact the entire open source world got less than one word per thousand in those books - and most that was either wrong or mere fact free filler quoted from third parties.
There are a number of reasons for this sad state of affairs, but the most important is one you might not expect: competent instructors tend to see the PC use in these books as illustrative and therefore acceptable - without understanding that their students lack their experience and see the PC focus in these books as exhaustive.
That's why we get stories, and not all of them apocryphal, about newly minted MBAs demanding that IT give them a copy of SAP to run on their laptops, about newly graduated CA (or CPA) candidates who expect to be able to sample Fortune 5000 transaction files using Excel, or about a former SuSe developer who got rejected for an interesting job at IBM because he lacked Linux experience.
On a personal basis I run into this all time time -with the vast majority of non technical decision makers not just clueless about technology in general and Unix in particular, but ultimately basing their certainties about Unix on cost comparisons between the Wintel ad they saw over breakfast and possibly decades old memories of painful purchases from HP or IBM.
That's the anachronism, by the way, at the heart of Red Hat's strategic plan to get to Redmond through Mountain View - by pretending that Linux isn't Unix they can get a lot of people to review the numbers on the Linux side while silently assuming that Unix cost experience from years ago continues to apply.
I find the general level of voluntary ignorance about Unix infuriating - although it does have its comical side. For example, I was once got caught in a touchie feelie interview process (I'm an ENTJ - duh.) that quickly degenerated to the level of the one question I actually remember: "if you were a vegetable, what vegetable would you be?" I said "rutabaga", and of course nobody got it - although I"ve wondered since whether the conclusions some of them drew from my choice might explain why I didn't get the job.
Unfortunately the consequences of this kind of ignorance can be both expensive and organizationally limiting because the IT related decisions senior management makes are conditioned by the things they know for sure - the assumptions and certainties they're not even conscious of. Thus your CFO may be the victim of anachronistic thinking or a poorly researched, poorly thought through, IT textbook - and therefore add unnecessary cost throughout your organization because he's known to accept decisions to add more Windows servers as part of the cost of doing business while sharply questioning recommendations to buy Unix.
So what can you do about it? In the short term, probably nothing; but in the long term you beat ignorance through education - meaning that we all need to ensure first that we know, and secondly that we spread that knowledge to others.