Linux on the desktop is hardly dead, it is alive and well and growing.
This is a really optimistic take on it. Here's some stats:https://www.netmarketshare.com/operatin ... pcustomd=0
It's gone down a little in the last four months but it's sitting at 2% right now, which I is about the same as last year but up from 1.5% in 2014/2015 and down a little from the end of last year. mac OS is sitting at around 5.5% for the latest three versions. Microsoft, even with making Windows 10 a free upgrade for as long as it did, is sitting with about 25%, and the old Windows 7 OS has nearly double that.
I don't think we'll see the 2% of "Linux" significantly increase simply due to the way Linux is distributed/developed. Microsoft has "Windows". Apple has "mac OS". Linux has... a thousand different flavors. You don't install Linux on a computer, you install Ubuntu, Fedora, whatever. They'd have to pick one to push above all others for marketshare to have a chance.
Also, there would have to be a "they" to make that push. Because right now the Fedora devs could come out and say "everyone should use Fedora, let's make that the standard" and then the Ubuntu guys will say the same thing, then the openSUSE team, etc, etc. (actually, I think this is how it's already done, which is why there are so many distros in the first place, everyone has a different idea of what direction desktop Linux should take, and the strength of being able to make that a reality is also a weakness).
Valve could make a push for SteamOS on PC-based gaming systems, and they sort of are doing that, and that could possibly increase the install base, but SteamOS isn't exactly a desktop operating system. Also... there isn't a need for it. Windows + Steam Big Picture mode is enough for most. There's a lot going against it, too. There are a lot of games, big hit games, that came out years ago that still aren't available on SteamOS/Linux, so if I want to play Skyrim, which was just a huge, wildly popular game, I have to do it in Windows. If I want to play World of Warcraft, I can't do it in Linux (well, I can, as long as I don't mind greatly decreased performance and the threat of having my account incorrectly detected as cheating and being permanently banned).
And even if all that were to happen, there'd have to be some need for it to get people to actively move away from Windows. You can make any number of arguments for the benefits of it over Windows, and I expect I would agree with a lot of them, but the key would be getting the "average user" to care. And for a lot of them it's just easier to buy an iPad or something.