Your post is vague enough that I have a hard time parsing it. No evidence for what? That there is such a thing as a "non techy" user? The evidence is overwhelming, including anecdotal evidence from practically every "techy" person here who have ever had to help their family/friends with a computer issue.
And it's not a question of ability, it's a question of ability + caring enough. The non-tech people might not care to boot an OS from a CF Card -- certainly not enough to seek out how to learn it.
To mom-type:
Here's an iPad, you can use it to easily email your friends, check facebook, and check the web.
or...
Here's an iPaq 2012, you can do all the above, but it's a little harder to use, HOWEVER you can boot any linux distribution you want, add a USB device, attach ANY keyboard -- like one with mechanical switches! I personally prefer the Cherry Blues, but you might want to try the Topre ones. People who use those never go back. They cost a bit more ($~250), and you have to get it imported from Asia or find a U.S. distributor... but it's worth it.