Because none of these OSes offer any of the apps people use and want, Same as with Linux and Windows, the vast majority choose the latter because that's where the industry leading applications (Office, Photoshop etc) Drivers support and best games are, Period.

People buy Windows, because it's hard to buy computers at the store that have Linux on them unless you know where to look (or buy locked-down Chrome OS). People don't need MS Office (Libre Office) or Photoshop (GIMP). Games run fine on Linux (see GOG and Steam), and the number would increase if more manufacturers sold laptops with Linux. Most people don't choose their OS -- they are fed.

People buy Windows because they want wifi to work

I've never had a problem with wifi on this laptop, and I use many different wireless hotspots. When it does happen, it isn't a problem that originates with Linux.

nice, there's 1 configuration that works... I've had 5 that don't.

I always research the hardware for Linux compatibility before I buy computers. Thinkpads tend to work well.

Windows Mobile, BlackBerry OS, PalmOS, Maemo, Nokia S-Series all had the top 100 popular apps at the time. MS for instance spent $$$ ensuring that was the case.

Edit: forgot the Kindle Phone..