Right; I just mentioned the kernel because it's the only thing I know of with consistent stats on what companies are contributing (and I mostly skip over those anyway). I just don't know anybody who publishes the same for, say, Gnome. It probably doesn't help that the boundary between the various projects need for a desktop Linux are blurrier.
And lets not forget the Torvalds policy of "we do not break user space". This makes it hard to get new stuff into the kernel, because any interface between the kernel and userspace that the new stuff expose will from that day on be set in stone.
The desktop devs on the other hand seems all too willing to break existing interfaces, treating them more like internal code than something exposed to third parties.
Sure, everyone loves if stuff just works - but if I'm looking back to my first years of Linux (1998-2007) and the last (nearly) decade - I haven't actively cared what kind of kernel, what version of kernel or whatever I am running on my laptops or servers. It just works[tm]. I'm really not trying to downplay the kernel developers' work - but if you're not using the latest hardware or need the last bit of performance.. many people could live with security fixes alone (hey, surprise, all the kernels in LTS distros only do get security backports).
(For me at least) in the last 5+ years the real development was in userland (for better or worse) - but I've stopped caring for anything besides "works fine" on a kernel level. Sad? Maybe.