I think the average user understands better than you give them credit, since OSX, iOS, Android, and Windows RT/Phone have fragmented the device OS market... The computing scene is no longer a MS monopoly, but is fragmented between a bunch of incompatible OSes. Nowadays that means you buy peripherals that adhere to standards, or that don't. It's in the manufacturers' interests to create products based on standards, which of course will work with Linux...

When my wife sees that her iPhone is a pain to connect to the computer, to her car, can't mirror to our TV, etc..., yet her Android tablet does perfectly, she doesn't blame the computer, car and TV...