Linux still not ready for some (most?) average users
I tried to switch some family members to Linux a couple years ago to get them off of XP.
Initially they were pleased with the new graphics and animations. Then, the hard questions started.
"Where is my iTunes?" ... well, I set them up with the default Ubuntu media player so they could play all the music they had already downloaded from iTunes. This seemed to satisfy them for a few days (or they were just being polite) but ultimately they told me they wanted to use iTunes proper, partially because they like to use it to find new music.
"Why won't [streaming video web service that I pay for] work?" ... turns out it requires some sort of Silverlight (?) DRM that isn't implemented or supported for Linux but works fine for Windows and OS X.
"Why won't some of my old Office documents open correctly in my new Office [LibreOffice]?" ... by this point I was getting tired of tech support and just bought some Windows licenses.
Now I'm sure you can make a million well-reasoned arguments about how people shouldn't support DRM'ed content or proprietary content services or non-standard document formats and all of that, but ultimately your average user is not going to care about your well-reasoned argument and will still want to run iTunes or whatever.