First, it's only been about 15 years at the most, and second, yes it is. Back in the late 90s, installing Linux was not really an easy process and took some expertise and a lot of screwing around. Now, you just put a Linux Mint .iso on a thumb drive, pop it into your PC, reboot, and follow some prompts, and after a half-hour, viola! you have Linux installed. It's easy as pie. It's quite easy to use these days too, as long as you don't use stupid Gnome3. KDE works wonderfully for both advanced users and users coming from Windows.
Oh, ONLY 15 years.. and they STILL don't have even a quarter of Apple's desktop marketshare. And really, you can make Linux as easy to install as you want, average people will never install it! They won't even download it. If it doesn't come on their new PC they picked up at Cost-Mart, they'll never bother, because people just want to turn it on and use it, not spend all day configuring this and that obscure option. Because most users are not computer enthusiasts. Most users are not programmers or graphics designers, and I know for sure that most graphics designers don't want to mess with their computers which is why they all typically use Apple. I take that back, the graphics designers do love to tweak their themes.
What future of computing? Are you one of those morons who thinks we're all going to abandon desktops (/laptops) and do all our programming, graphics design, word processing, spreadsheets, etc. on our cellphones and tablets?
The future of computing is desktop PCs. They aren't going anywhere, for doing serious work. For some tasks, like watching videos or reading e-books, other devices are taking those roles over to some extent. People are doing more things with computing devices, so the market is expanding, and mobile devices are enabling usage that was either impractical or impossible before. This doesn't mean that desktops are dying, it just means they're a mature market.
The future of computing is back to the old server/thin client models. Streaming services out to users on tablets and phones because if the phone's hardware can't handle your "serious work" then they can stream from a custom VM over the network. The future of computing is the millions of low wage workers in Africa, China and the like who don't have the money or the infrastructure to support a PC but everyone has a damn smart phone.
Also the idea of a "mature market" for PC's is exactly why Linux on the desktop has no hope! The market is mature! It's settled in with Windows and OS X and there is no room to disrupt that with a Linux desktop no matter how damn amazing it is. The only, ONLY 3rd option that has made any kinds of inroads has been the Chromebook, which completely throws out the desktop concept.
So you are one of those morons. Did you type this post on a phone?
No, I didn't post it from my phone. I didn't post it from Linux either, jerk. I did post it from my Asus Transformer tablet running Windows 8.1 though.
What software? Steam runs fine on it, and lots of other software has moved to running in web browsers. People are using less and less proprietary software, and desktops are becoming more confined to being used for specific apps: web browsers mainly, plus office apps.
And why exactly, if in your own words desktop software is being funneled more and more through the web browser, do we need big honking desktop machines then? An iPad with HDMI to a bigger monitor and a bluetooth mouse/keyboard can run all those web applications just as well, and with a lot less electricity being wasted, as your desktop machine.