With several dozen million Ubuntu desktop users worldwide[1], Canonical has become the gravitational center of the FLOSS desktop and a promising platform for other form factors. No other FLOSS desktop comes even remotely close in terms of mass adoption.
As a consequence, many other FLOSS projects that historically have perceived themselves as more important "upstream projects" to the Ubuntu desktop have now become, effectively, contributing projects to Ubuntu. It is now they who depend on Canonical to reach and interact with the vast majority of FLOSS desktop users.
For the individuals who identify themselves with those other projects, this tectonic shift in power has not been enjoyable. More and more of them are gradually realizing that if they want to continue working with Canonical, it will have to be on Canonical's terms.
--
[1] There were over 25 million Ubuntu users at last count: http://blog.canonical.com/2013/10/01/ubuntu-pre-installed-an...