I'm running Ubuntu 15.04 and it's broken in so many basic ways; like, it crashes when you open the calender widget on the wrong day of the month, apps only refreshing the UI when you move the window around, isn't even able to format an USB stick with FAT out of the box, etc.
I can't back it up with numbers, but my feeling is that desktop Linux has peaked around 2010 (Ubuntu 14 LTS), and is regressing since. In times of shrinking desktop usage, rather than inventing new stuff all the time, it'd be nice if distros could focus on providing a robust runtime environment for the OSS desktop software we have. Maybe I should use Slackware 14.2 (systemd-free; its setup on modern hardware with nvme, uefi etc. seems painful, though).
But I'm not complaining; all the work is done mostly by enthusiasts, and commercial OSs don't work well either.