It has a broad appeal, but one thing you forget about the open source community is that they are generally stuck on "free" and therefore are as cheap as they can come.
Throw a premium cost product at them and they immediately have the logic of "I can build it cheaper myself" even though it's impossible to do so in this case.
Not to mention anyone that isn't already running Ubuntu doesn't really care and is probably scared of it.
Some truths in there. Yes, a lot of the FOSS community is "cheap" with very few donating anything towards the distro they use. That being said, most of the distros do no cater for people outside their country.
Arch is my poison, I cannot donate to it because they only accept credit card payments. I would, on a regular basis, donate a small amount, and have done so for Gentoo and other projects in the past, it is just a headache getting around the international financial barriers.
The problem with Ubuntu is that they have alienated themselves from the rest of the FOSS community, a fact that I have pointed out on many occasions here in the past. They do not really contribute unless it is for their own gain.
Just a few examples off the top of my head:
They do not support other WMs and DEs, they have to have Unity. I know they are all about setting up a mobile platform at the moment, but there was projects with KDE, for example, working very well on mobile platforms in the past. Instead of taking Gnome forward and adding mobile support to Gnome, they start their own thing. (I am aware of they attitude of the Gnome devs as well, but I really feel they could have worked things out.)
Wayland is the next industry step toward X server, yet again Ubuntu is doing their own thing creating
Mir. Don't help and fix or better Foss as a whole, we will just do our own, independent, thing.
And this is going to be the corporate downfall of Linux. It will be very interesting to see how Nvidia and Radeon respond to Mir, for example. Is Ubuntu big enough to force the Linux desktop in a direction of their choosing, since hardware manufactures cannot support everything out there, they will have to choose at some point, Wayland or Mir.
Very few FOSS big hitters are backing Ubuntu, and that is why so few care. If you constantly throw sand in the eyes of your other playmates while in the same sandpit, you'll end up being all alone.