why would they? The market for Windows, OSX, iOS etc dwarfs the linux-on-the-desktop market. It's business. Linux is for servers, OSX is for clients (and pesky Windows for the office because IT says so)
I don't see this changing anytime soon, and this discussion has been thrashed to death, I think that there will be dwindling support for Linux with desktop apps. The best you can hope for is a browser solution and that Chrome keeps building on Linux.
That's silly. There are far more linux desktops than there are servers, and this is growing, not dwindling. Just because you don't like it as a desktop, doesn't mean reality isn't real.
No offense intended, but "citation needed". My intuition is that server side Linux is a lot less visible, but outweighs desktop use by a good margin. Eg. I run desktop Linux on 2-3 computers at home, and 200+ servers at work.