Windows 8 runs games.
Ubuntu? not so much.

Windows also has a LOAD of software that the Linux community can make mimics of.

If you're using a PC to surf and listen to music, Ubuntu as an OS is excellent.
it even lets you get a little fancy and do some neat stuff, should you feel the urge.
but will the average user feel comfortable using it?
noooope nope nope.

windows is what people use,
so they inherently feel more comfortable with it, even after a new version is installed.

the reasons you listed, author, don't really apply too much to a normal user.