Each to their own, and of course finding an optimal writing environment is a very subjective thing -- but it's not like there aren't modern distraction-free writing interfaces that exist.
Then again he's also about a decade late with the next book
Usefully showing end-of-line markers. I remember thinking compared to dec-10 ROFF (which iirc proceeded nroff etc) it was both simpler and harder.
Used it, never liked it. Ed was the way.
I'm not sure how I would get my files I create off the device since USB support isn't really a thing.
I think the below-mentioned Pocket 376 might have one soldered-on already.
Or just run joe as jstar and close enough, maybe? I use joe for mostly everything, but I never used WordStar (well, I ran into it once)
It's still early and I'm struggling to write more than a few lines at a time. Not surprising from how I've been commenting "witty" one-liners in comment threads for over a decade. I expect being able to write long-form with no backspacing will need a lot of time to learn.
But I want to take back my attention. If there's one thing I've learned in the last decade, is that one's attention is a precious resource and it's time to be more deliberate in how I spend it.
Only start editing when a substantial piece is ready. Clean up some wording, rewrite a paragraph or two.
Even then, don't overdo it. There is always something to improve, you'll never be done that way. Good enough is good enough, hit publish and go on write the next thing.