At one end are the people with the computer knowledge you mention.
At the other end are people with very little computer knowledge.
It's all the people in the middle with a little computer knowledge who will struggle when they try to manage files.
But the experts will expert and the uninformed will just use the computer to do the high level tasks they do (e.g. browse and email and store everything on the desktop). Modulo obscure hardware, Ubuntu will just work for them.
Which is not to say this is the year of the Linux desktop.
Harder but easier and less challenging. The distinction I would make is for users who are comfortable interpreting the command line and those who aren't. That comfort level is what should dictate the user's decision to opt for linux vs windows/mac.
(PS: IMO, mac power use often requires the CLI, but macOS has built-in some guardrails to prevent noob users from completely messing up the system. Linux has no such guardrails).
Have you guys even used linux in the recent years? Sure it's a bit janky sometimes but so is windows and only getting worse. You can get quite far with linux by using graphical package management apps only, and now with steam you can even install games as easily as on windows.
Linux is way easier and more intuitive to use even for a novice than windows. I don't get why people think windows is somehow easy to use.
The use of the command line stopped being mandatory years ago. Everything that an average user is likely to do can be done though the GUI, just like other OSes.
Why would you need to do that?
How is that relevant to someone switching to Linux desktop? Android is also Linux and also not relevant.
