Imho text editing speed is not an issue for programmers.
This is at the core of why vim/others are still so popular. The micro-gains in typing efficiency translate to much more efficient problem solving because you don’t “lose your place” within your mental process. I think the same would extend to cursorless.
I guess it's a bit like navigating using only the map in the war room vs navigating on the ground without a map. The ideal route comes through a combination of both, and typing allows for the latter point of view.
Though after typing for a while, I'll take a step back and think about the overall solution again, going over it in my mind. Then back to typing.
That said, I gotta have a responsive editor.
In terms of just typing, I could probably produce something like 50,000 lines of code in a 40 hour work week in a moderately verbose programming language. In practice I'll probably crank out somewhere between 1000-5000.
It's the thinking that is slow. It's made even slower by adding additional tasks and context switching.