"constraints breed creativity" is the idea that you can end up with a better, more versatile solution -- rather than copping out at the first "good enough" solution. Of course, it's not guaranteed, but still. It's certainly possible that arrow keys are a mistake for total performance (arrows are trivially more visible, but also trivially greater motion from your other work). It's also certainly possible that modal editing is simply more effective than mouse & hotkeys, even if they were only designed because the mouse wasn't available.

Now, escape vs caps-lock-position, I'll give you freely, but generally its fair to judge a design based on current constraints, but not to judge (& discard) a design because it was designed other alternative constraints.

People continue choosing to use vi-keys (via vim, nvim, or even the many vim-emulation layers all over the place), even on modern high-speed connections, precisely because they still find "single character commands and the ability to type ahead of the display" valuable.

"The display" does not have to be a terminal display. In fact, a significant number of places vi-emulation is used don't even support terminal displays. "The display" can be anything the human waits for to reflect the actions of keys pressed. Once you consider this, the efficiency benefit of vi-keys becomes as clear as that of touch-typing.

The ADM-3A no longer matters. Vim does not use vi-keys because it ever targeted the ADM-3A. Similarly for Neovim, Evil, Tridactyl, Vimium, GMail (and so on). When I wrote a new vi-keys layer for a toy terminal multiplexer, I didn't use h-j-k-l for navigation because I wanted to target the ADM-3A — I didn't even know about the ADM-3A! I did it because I knew of the benefit of using those keys, even on the modern 100+-keys QWERTY-layout that I grew up on and still use.

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> .... my gigabit fibre connection.

> You're reading this on a phone? Is it 5G? Then it's faster than my fibre.

I cannot describe enough how much I hate this discriminatory excuse, and I live in the top two cities with the best internet connectivity in my country (for four years of my life in Mumbai, till 2020, I was one hop away from the Mumbai IXP). It is downright shameful how far people will stoop while using this excuse. An absolute minority of the population thinks it absolutely okay to build software that excludes users who don't have the absolute best hardware, just because they live in cities like SF or Seoul and are blind to the conditions of other humans. Most of these people aren't even aware how they are excluding people; that's how little they care. I can only wonder what the overlap is between this set of people and those that ignore accessibility.

You are fortunate enough to have a gigabit fibre connection (and possibly 5G) connecting you to servers from your continent, most of your time. But that is not a right you can expect others to have, and that fortune is far from universal. I am fortunate enough to have the access I do have when I have it, but I can only sympathise with the plight of those in Australia.