Because more people are using GNOME than KDE. Here is something else, according to some folks within suse, opensuse also has more GNOME 3 users than other DEs
Where are you getting these statistics from? Are you just extrapolating from assumptions like: Will not change the default desktop?
I would be more interested in seeing what the repositories are reporting concerning updates... but even that will not be accurate because sometimes I leave stuff installed for testing purposes... and I am sure others, for their own reasons, leave stuff installed too despite using something else.
For myself, I consider Gnome to be of the same type of evil as SystemD. The developers are utterly infatuated with their own ideas and incapable of understanding that their ideas are just not that good, despite solving some very real problems.
Honestly, I am unsure why I am even commenting. As a former Gnome user, I feel glad that someone wrote some decent software that I could use but I am not forced to use Gnome... so I will do what I will do, and that is not use Gnome now. I am rather angry about SystemD though. THAT is getting foisted upon me whether I like it or not. It is entirely possible that if distros do not fight against SystemD that it may very well kill Linux. SystemD makes Linux as reliable as the toy operating system called Microsoft Windows.