Maybe Ubuntu (or mint?) has learned UX design and found a way to sand down all its' rough edges in the 3 years since I switched to OSX, but I doubt it. Running linux requires the time and patience of a knowledge person. Linux is far too expensive for most people.
Even with "consumer friendly" distro's like Ubuntu compatibility is an issue and you can easily screw up co-hosted software and even the entire OS due to the current dependency mess which plagues the F/OSS world especially on Linux.
Back in the 90's and maybe maybe early 2000's you would get silly error messages like .dll XYZ or cannot find ZYX .ocx on Windows but today? I don't think so, other things like configuring network sharing, backup, more advanced network setups are still considerably much easier on Windows than Linux.
And it's not just the UI both Gnome and KDE have offered pretty much 95% coverage of anything you can configure on Linux (core service only ofc) in the UI but their UI is still sucky.
I haven't used Windows server since 2003 jumped into 2012 and could find everything and any new features were self explanatory, trying to make OS changes in Gnome, meh i rather just find the config file and edit it manually.
Linux needs to get It's shit together, and hopefully one day it will, because ATM even with all the nice and user friendly package managers at best half of your software will come in archives which a basic consumer user doesn't know what to do with (nor should they) and at worst comes completely uncompiled forcing you to /MAKE it on your own machine hoping you got all the dependencies and the header files you need.
And for the software you can get from your distro's "app store" you still holding your fingers hoping one application wont cause all of your other ones to brain fart because the dependencies it uses are of a slightly newer or older version.
I've worked for a Company that tried to switch their desktops to Linux, and I've heard plenty of stories of people who encountered similar cases, it just never bloody works just like everything else and then they panic hire an entire new IT department who still doesn't manages to get everything working properly for everyone and scarps the entire project 6-8 months down the Line losing probably several orders of magnitude more than they would ever have gained from reducing licensing costs across their desktops.
I've used various linux distros for years, and there's always something that doesn't work right. Whether it's the speakers not turning off when I plug my headphones in through my thinkpad dock in Arch, or monitor position settings changing every time I reboot my desktop in Elementary OS, the lack of polish really shows. I understand why this happens, and I don't fault the people making on the various distros. I've even dove in and fixed a few problems myself.
But nevertheless, it remains a problem, so for now I've just decided on windows for day to day use with a VM running linux when I need it.
More importantly Duck Duck Go is actually considered worse than Google even by many people that use Duck Duck Go so this is considered a significant feature. Granted, it's debatable how much worse but Bing / Duck Duck go are viewed as competitive search engines not better search engines. Plenty of people are doing regular head to head comparisons with people using different search engines for the same query if they can't find it on one they use the other. After a while the 'better' engine generally becomes their dealt.
Windows on the other hand has a lot of inertia due to third part integration. For example there is a much smaller selection of games on OS X than windows which creates a feedback loop. There is no way OS X could hit 50% market share in 3 years let alone a brand new OS starting from scratch, but search has seen massive swings in market share fairly recently.
PS: The g! feature is also great for fine tuning their search engine. Providing a listing of every pain point when people gave up.
These tools will be interesting to use for a handful of techies like myself, but Google will remain safely ensconced in its fortress of cash for at least the next several decades regardless of this and whatever else comes along that may enable the creation of superior search engines.