I have recent experience of this. My 71 year old father recently got his first ever computer. I've been around computers since the days of the ZX Spectrum, have used everything from DOS, most flavours of Windows, OS X and Linux, so it was a real eye opener to see how difficult it is for someone with absolutely no previous experience.
He's intelligent and willing to learn, but even basic concepts take a lot of time to get across. I'm lucky in that he lives reasonably close to me, so I can show him things. Trouble is, he's got a Windows 8.1 laptop, and even I find that frustrating and counter intuitive. I thought it might be easier for someone with no previous expectations - he's never used other versions, so the changes shouldn't bother him - but the mix of metro and desktop applications is just so counter intuitive. I had tried nudging him towards a macbook, but he couldn't justify the price difference. Perhaps a chrome book would have suited him better, but it might have been too limiting.
I dread Windows 10 and having to start again, I know that. User friendly is only user friendly if you're already familiar with computers, but I suppose it's a problem that will fix itself when the generation that never used them dies out.