But there are professions in which these tools play a much bigger role than mine, and I see these people using Microsoft Office everywhere, often barely able to open plaintext files. I really want to understand why. Am I missing some advanced Office features? Is it just lack of experience on my part? Does my experience with programming languages or Emacs play a large role? Is Microsoft's influence and lock-in too strong?
There's nothing wrong with that. Plain text has its place and its user base. That user base isn't just technical people, either. WYSIWYG tools have their place, too.
I think it's related to visualization of hierarchy, emphasis, relationships, images etc. It's just harder to see the layout of a document in plain text, esp for people not used to doing so.
Of course thats not to say the visualization could not be built on an underlying plain text markup, it just wasn't in MS or Googs interest to do so. It is encouraging that a lot of the new wave of PKM tools (Dendron, Obsidian, LogSeq etc, plus my own, BrainTool) are built on a plain-text first model. Maybe its making a come back!
However, WYS* apps can do what most people does with text files and then some. I believe using text files are limited to those who are superusers or programmers, etc. (with exceptions of course)
This can only stop when various polities adopt Linux (like in Germany where some region is switching to Linux). This means they have to be well versed in LibreOffice, which is decent enough, although I am hearing reports that it has rendering flaws for .DOCX documents, so it's not a silver bullet.
Check out vfat.tools it is a staking pool search engine (kinda sorta not really) and I love how it uses a fake .txt file interface. Obviously it is just an illusion but I still like it