> I don't think the author really understands why people choose not to use linux, it's not because of the window managers.
No, just as with the vast majority of other choices, it is heavily based on marketing signals. People either do not choose at all or they do so driven largely by emotions.
How many people do you know who tested rationally and objectively their choice of operating system, brand of mobile phone, model of car, location and characteristics of dwelling, etc., etc.?