Most of the comments here are talking about the x% of time Linux gets messed up it can be really intimidating for new users and getting the right help can be a challenge, or simply more time than it's worth.
I think this is true, but I think there's another thing that irks people:
Software Compatibility
The general public primarily interacts with their computers through established applications that commonly aren't available on Linux w/o intimidating work around (if at all).
A noob who switches to Linux isn't going to know the limitations up front, and the second they decide they want to learn Adobe Premier for work, they're kinda fucked. They'll either spend hours/days of online research trying to figure out if it's even possible, or they'll ask for help only to have someone tell them they're wrong for trying and to use some FOSS alternative because Adobe is an evil megacorp.
It's a recipe for frustration.
I like A a lot, reminds me of the early iPhone days of tasteful skeumorphism.
B is probably my favorite tho -- definitely the cleanest.
C looks off to me, something about the goggles.