Statistics, statistics ....
The problem I have with Schofield's analysis is he is using percentages. In one way it is not as meaningful as showing absolute numbers. For example, if there are a 1000 Windows users out there and 100 more people buy a new (or first) PC then the percent just for Windows is 10%. Now if you have 100 Apple users and 15 people buy a new Apple PC, it is also a 15% increase, but overall 15 out of 1100 is a bit more than 1%. Now if you have 10 Linux users and 5 people hop on the Linux bandwagon, you have a 50% increase, but less the 0.5% overall.
One thing that will hinder Linux catching on with the general public is Ubuntu's switch to Unity. To many in the Linux community, it is as bad as Microsoft switching to Metro (or whatever). The Gnome 2 desktop had sufficient familiarity to XP and earlier Windows versions - even Windows 7 (which has generated a lot of complaints from XP users). Other distros, such as Mint and other Ubuntu/Debian based distros, have different desktops and they are also affected by the move to Unity and Gnome 3. I have used the KDE desktop and, while it is OK, it is not Gnome 2. Now you have to install MATE or something similar to get the look and feel of Gnome 2. ZorinOS and SolusOS are trying to pick up the slack, but it will take a while before they gain popularity within the Linux community.
Remember, when you are posting on this type of web sites, you are not the average (or typical) home user, whose knowledge of PCs is extremely limited. They know how to log on, do e-mail, surf the web and maybe one or two other basic functions. One reason why tablets are so popular - a lot more portable, similar to their I-Phone (or clone) and do the basic functions. Typically, the e-mails sent are short, one liners (send from my I-phone) and/or pictures of the kiddies taken. Probably why Microsoft "seems to be abandoning" the desktop - they figure the business world has technical personnel (or access to a tech person) who can lead them to the desktop they have come to know (and, some, even love).