I've never seen anyone aside from devs running a linux desktop device, so while I'm not saying this can't be right, I am a bit sceptical. For an average user, Linux can still be quite challenging to use as their main OS.
My wife uses Arch on her laptop - she doesn't really know what it is and doesn't really care. She does know that she has less down time than with Windows when updates happen. She uses Facebook (the internet sigh) very heavily, email (Evolution to an account on my office Exchange server) heavily plus a fair few other things - basic word processing and spreadsheets via LO.
I'm a KDE aficionado for good reason. I put a few large icons (KDE allows you to scale your icons really well) on the desktop, with a pretty wallpaper, that have easily understandable functions, that are locked in place. The ability to lock the desktop layout is a killer feature that I do not see available on Windows or Mac or most Linux WMs.
Obviously, it does help that I'm an IT Consultant but "For an average user, Linux can still be quite challenging to use as their main OS." No it doesn't need to be so. The KDE Plasma UI can be made very simple or unbelievably complex to suit the required UX.
I've installed Linux on family member's computers before just to get calls when an update broke the graphics driver.
Just try and let your wife install and update Arch herself, I'm sure she'd give up quickly.
That being said, most users just need some icons and a web browser, almost any OS works for that.
A few months ago, I saw one of my dads friends (my dad is 59) share a product that you plug in via the USB port on an "old laptop" and it brings life to it. It was no doubt a Linux distort on a USB stick. The product claims to bring life back to old slow laptops. If he can get excited about it without understanding what it does, and we know once you have a USB stick running Linux you're pretty much golden depending on how much you want to do, well he would probably enjoy running Linux off that USB stick and not know the difference. Just tell him where the "Internet" icon is. Also many older people adopted iOS and Android and I never had to stand by and explain it all to neither of my parents despite them not being Windows based devices. People adapt. Just hard to say what caused this Linux spike.
I would add, I think it's a bit simpler then that - practically nobody sells computers with a Linux distro preinstalled, and that's the only way an average user is going to get one.
