In 2010 Ubuntu was the best shot the Linux community had at getting serious market penetration into desktop and laptop computers. With GNOME 2 it wasn't as pretty as Windows Aero but the user interface was similar enough that the switch was easy for regular home computer users.
Then Canonical switches gears to Unity. The first few releases were very buggy, and even after it was quite stable the user interface changes annoyed people. So Ubuntu ceased to be the default suggestion for a Linux version to try to Linux newbies, and there really wasn't any new contender to replace it.
Linux Mint gained popularity rapidly from that, as it offered user interfaces and customization options in line with what dissatisfied Ubuntu users wanted. But Mint doesn't have the same chance at capturing a significant piece of the standard desktop market. Their recommended upgrade process is still a fresh re-install ( see
http://community.linuxmint.com... ), which means it only works for technically skilled users.
Now, Ubuntu and Unity are open source software and Canonical is a business, so they have every right to change whatever they want for any reason or no stated reason at all. So I do not now and did not then hate Mark Shuttleworth or the Ubuntu developers or Canonical employees for the change. I just feel like a great opportunity for Linux to enter mainstream use was wasted and all that momentum that Canonical and Ubuntu built in user base and press support was splintered.
The next great opportunity for Linux to reach user in mainstream desktop computers is probably SteamOS, and while I admit that I'll probably run it myself, I am not pleased that a proprietary digital rights managed software distribution platform may be the lever that makes Linux mainstream on home computers. ( Really, I should put my money where my mouth is and support one of the Ubuntu alternatives that could become equally good for new users with some work. Fedora? OpenSUSE? Debian? )
And to be fair to Canonical and Ubuntu, I think mainstream (non power-user) computer users will be mostly on mobile in the future. So even if I dislike the Unity user interface, I can understand trying to invent some alternative to existing desktop environments that would work well on mobile devices. I understand where they're trying to go, even if I think the direction they took is a mistake.