Nonsense. There are billions of Android devices sold and customers don't seem too bothered by its fragmentation. They continue to buy Android devices en mass.

So it seems fragmentation has many problems but that alone won't prevent people from using a device. I think the author believes that a critical mass of Linux desktop users will create enough interest in polish and solving problems for end users, so therefore believes if everybody was using the same desktop there would be more polish (or something).

I would counter that the desktops have plenty of polish. He says he loves the Linux Desktop and doesn't offer much criticism besides there's too much choice. Nah, they're already great and we don't need to abandon great desktops.

Instead, I believe other factors are at play. Familiarity, inertia and monopolistic competition to name a few. Those are powerful factors and much more so than abstract fragmentation.