When you spend all your time at a prompt you don't really care about unity vs cinnamon vs anything else.
Debian is stable and has fantastic package management, and Ubuntu builds on that with a vibrant community and wide support. For these users, Ubuntu 'just works' and lets them get on with what they want to do. It's about as simple as that.
If I am honest, I spend 90% of my time in a terminal, browser or editor (which is also in a terminal), so give me a system that allows me to easily install my most beloved programs via command line and handy binary packages, a system that is reasonably stable, runs on most hardware, and that has a big community and a lot of documentation, sounds like a good deal actually.
What I originally thought about were systems like NixOS (for serious development), or something more minimalistic that offers greater control like Slackware, a *BSD (Jails, byhyve, dtrace(!)), or even just Debian (less flashy, more stable and robust).
Xubuntu is medium light for me and is fast. Previously I had only fluxbox on Kubuntu for the KDE apps which was extremely fast but with bugs in fluxbox I switched.
Why am I seeing Ubuntu on Screens of developers, experts, et cetera in Cover Stories such as these, most of the time with the 100% plain Ubuntu Desktop with all the craziness that comes with it? It feels like this is the case 90% of the time. Two more (recent) examples I can remember:
1) Fyodor (Guy behind nmap) running plain Ubuntu on a Notebook while giving a speech at a conference
2) Developers at Honda (Video was an Asimo promotional video) running plain Ubuntu
Since in my personal opinion Ubuntu is not the technically superior choice in these cases (though that can be debated), it can not simply be explained with it being backed by a company, there being support you can buy for the system if you need it.
What motivates technically extremely skilled people to use "Plain Ubuntu" instead of one of the many alternatives?
I really don't understand, please enlighten me!
(I actually think it's worth "spending" some Karma on this if I for once get a satisfying answer)