I've used Emacs for over 20 years and I have been meaning to switch to vi keybindings for a while (but haven't yet :). I just find myself executing long commands with only 4 of my fingers engaged, because one of them is holding a modifier key, and it's somewhat uncomfortable. Not injury-causing uncomfortable, but enough to make me think "hey, I think the other team got this right." I would not mind switching between command and insert modes; I can keep the state in my head instead of in my finger.

The barrier to switching, for me, is that the vi-like modes are set up by default to have vi-like keybindings, and I just don't care to go in and change them all to Emacs-alike keys, and I worry how flexible other software with "vi mode" will be about that. I am past the point where I'm going to use hjkl to move the cursor around, I use npfb. I can easily change the details in Emacs/Viper, but then how am I going to use anything else, like the shell? That is my main worry.

It sounds like you would like god-mode: https://github.com/emacsorphanage/god-mode

I'm a light weight emacs user (mostly for org mode). I'm forever grateful to the dev I worked with who introduced and encouraged me to learn the vi bindings.

I'm probably missing something in your message, but there is support in the shell for vi bindings (https://opensource.com/article/17/3/fun-vi-mode-your-shell)

Exactly - with inertia, or maybe oblivious. I think it's just a little discombobulating to read about a program I spend so much time using myself being used in ways quite far away from what I know about.

That's a good thing I'm sure; it makes sense that a super-configurable extensible application should be super-configured and extended. But it's a little odd to imagine, perhaps, saying "oh this is Emacs? great" and then finding that you don't actually know how to work it.