The article really is 'right on' as to why the desktops are a dieing breed. Or, at least, are on their way down to a new plateau.
In the early days, and until the last 10 years or so, desktops had two markets...corporate and consumer.
The corporate customers embraced desktops as a means to interface with the mainframe as well as word processing, later email, spreadsheets, and a plethora of other workplace 'productivity tools' (HA!). That meant and still means a stable platform with no new daily surprises, bombouts, new releases, etc. To that end, that's why some of the bigger companies around here, including my employer, still use Windows XP. It's by far the most stable platform Microsoft has come out with. Win 7? That would require a major expenditure not only for new computers, but for the whole gamut of other software that works under XP, but not compatible with Win 7. And Windows 8? I don't see corporate users going to 8 for at least 3-5 years, and that's only because their XP machines are slowly dieing of old age.
For personal users, until 8-10 years ago, a laptop was secondary to a desktop computer. Then, as laptops got cheaper, the lastest upgrade to their laptop obviated the use of their desktop box as well...or their toddler-age kids got the old desktop. And now, with iPad and smartphones, except for hard-core MS Office users, and 'us' Photoshop/Lightroom/etc users, there probably isn't much need for desktop power and capacity any more.
When I started in computers 47 years ago, the biggest mainframe cost well over a couple of million dollars. My 10 year old Timex watch has a faster processor in it now. As computers get faster/cheaper/smaller by the day, the capabilities of todays desktops will soon be in iPad size computers with the bulk of the storage 'in the cloud'.
My younger brother does IT work for the Navy and, to this day, deploys Windows XP on brand-new computers. The Navy spent a lot of time and money learning how to lock down that OS. They have no incentive to move to Windows 7 (or 8 for that matter). It simply doesn't do anything new for them, and the software they use is mostly developed in-house, and thus there is no need to upgrade to remain compatible. I suspect the same is true for many large corporations.
I think Steve Jobs had it right when he said we are entering into the Post PC era. Portable, ARM platform devices like tablets and smartphones will dominate our computing needs. Beyond that, the laptop computer has come leaps and bounds. Most laptop computers now are more than powerful enough to handle the load of a typical user. They are much faster, and have near-desktop specs. The local high school here switched to all-laptops a few years ago for the teachers, AND the computer labs. It just makes sense! Less space taken up, less power consumed, and the price is similar! Years ago, a laptop was a substantially more expensive machine with substantially poorer performance. I remember the first laptop I ever saw/used. It was an IBM of some sort, had a giant protruding box out the back of it, it belonged to my neighbor and he spent several thousand dollars on this machine that my dust old hand-me-down computer ran circles around.
Nowadays, the gap has closed. Heck, look at Apple, they are embracing this method in both ways. Aside from the Mac Pro, everything they make is, essentially, a mobile computer. The iMac and the Mac Mini, though technically desktops, both use mobile technologies (mobile CPU, mobile RAM, mobile graphics, mobile Hard Drives), in a DESKTOP platform! For most users, a laptop will do everything they need.
There will always be a niche market. Those of us who have computing needs that require a lot more horsepower than what a laptop can give us. But I think the days of buying a desktop computer off the shelf are dwindling to an end. There will always be online-ordering of desktops or home-building for the rest of us.
Kind of scary to think back to just a few years ago, where technology was, vs now. I was watching Mythbusters on Netflix today from 2003 (season 1), that's not that long ago, but the technology looked of a forgotten ancient world. Gone were small suction cupped go-pro cameras on their various rigs (hoods of cars, cranes, etc.) that you had to squint to look for, instead everywhere you looked there were giant rigs with huge cameras. They used cellphones with protruding collapsible antennas. It was scary!
The first computer I built had a 33MHz processor, 2MB of RAM, and a 1MB video card that was bigger than my 1GB HD Radeon I have in my desktop now. It had a whopping 500 MB Hard Drive. I remember building a computer with a 6.0GB Hard drive, and saying "There is no way anyone could possibly fill one of these". HA! 6 Gigs wouldn't last a half hour in my camera, and that's being VERY generous!