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).
How is that relevant to someone switching to Linux desktop? Android is also Linux and also not relevant.
