Well first of all Linus has never been overly concerned with market share, just building a technically damn good kernel so I doubt this will have much practical influence on his work. It's got to be frustrating though, Linux works on massively huge and complex servers. It works on the smallest mobile and embedded devices. But a regular desktop that from the kernel's side is rather simple, one CPU and usually one GPU and pretty much no exotic devices (from the kernel side all USB devices look the same, for example) and no absurd limits being pushed in any direction.
I think the last real significant desktop feature was when they increased interactivity by changing the default time slice from 100 Hz to 1000 Hz and that was in 2004 or so. Heck, I would say it was at least as ready as the BSD kernel was when Apple created OS X in 2001. It's quite telling that the one thing Google did not want to rewrite when they made Android was the kernel. All else they ripped out and replaced with Apache licensed code, but not that. Well that and a bunch of Google proprietary APIs, but that's another flame war. I think I'd feel just the same in his shoes.