Something interesting I see more often than not when someone I know decides to try out vim:
They know I'm a vim user so they ask me for good tutorials and I tell them there are lots out there but they should start by running vimtutor (included with vim). Takes around 15-20 minutes to work through the interactive lessons and gives you all the basics of movement and editing.
A day or so later I ask how it's going and the answer is usually that they're struggling with vim, so I ask if they ran vimtutor. Usually nope, or they started it but quit after a minute or two.
Why would one switch to a tool with a different paradigm, ask for and get a tutorial recommendation, and then ignore the advice of spending less than 1/2 hour on a tutorial that ships with the tool? sigh
I think that I am rather good at memorizing lots of obscure raw data - but in my experience it takes a lot longer to remember all the "obscure" commands of vim. In this sense I would not say it takes 15-20 minutes, but at least a day if at the end you really want to have the commands in your brain.
In this sense the mistake in your argumentation is the timescale that you are talking about.
Also, I hold some fairly controversial opinions: you don't need dozens of vim plugins; you don't need to compete with vim golf champions; you don't need an extensive configuration.
What you do need is to fully grok the idea of normal mode as an editing language with verbs, objects, and modifiers. Once you "get it" then you have a working knowledge of how to construct "sentences", and learning a new text object allows you to apply pretty much all verbs to it. Same for learning a new verb; you can apply it to lots of things.
Over the years I've learned a lot of interesting vim things and I've forgotten most of them. Because I don't need them every day or even every week. That's ok. The things I remember are things I use often, because they're useful in everyday editing.
In Vim there are modes that describe sets of keybindings and there are commands that are bound to them. The commands themselves are are straightforward for anyone who's fluent in Linux vocabulary.
'Saving' is a Windows word. We :write to files or :w for short.
This is the very same narrative that vim users proclaim: "It's totally not complex if you took some years to learn your tools" — while simply not realizing that the whole Make syntax is a pile of clunks and hacks and stopgaps and bandaids that has a super steep learning curve and looks like incomprehensive gibberish to the uninitated eye.
And most of that needlessly so IMHO. It shouldn't be hard to find a better, well designed syntax with sane defaults, stricter rules with typing and linting, less surprises (tabs, I'm looking at you) that's overall much less scary for newcomers — as well as less taxing for "expert casual" users like me. (I still go for my coworkers and Stack Overflow regularly if I have to fix one and I'm a fucking CTO with 10 years of dev experience)
Make's only reason for survival is its ubiquity. No matter which terminal you boot up, it's just there, that's why we use it too, and I hate it every day.
I think none of the alternatives (cmake, Jam, Gradle, Maven, grunt etc. etc.) has really succeeded as a cross-platform, cross-ecosystem solution that's both an approachable, simple and usable version of a DAG execution engine that's usable for lots of situation.
So the situation will probably stay like with vim and the QWERTY keyboard, the status quo pretty bad, but everyone's too used to it to go for something better.