Like mentioned in the article, another issue is that there are very few offerings of computers with Linux preinstalled in normal computer stores.
You know how a normal average persons buys new laptops? They go to such store and look at the prices and buy one according to how much they want to spend. The advanced buyers might consult their more tech-savvy acquaintances. Stuff like "Just install Linux", is beyond concept comprehension for a lot of people, even if they heard about Linux at all.
All to say is that it's not like they can't understand these concepts if you explain them (people are clever), but they should care about them in the first place.
Edit: typo