I do think there's a "CrossFit" mentality among the typer-coders who swear by mechanicals and end up with wrist braces - a kind of "more is more" approach that drives them to write lots of code, put in lots of hours, memorize innumerable details, and min-max their output in Taylorist fashion. It's optimizing for reps, versus mobility, stability, flexibility.

I have let my WPM drop a fair bit over time. I'm still relatively young yet, but I see no reason to go fast when I realize that most of the typing amounts to disposable bullshit. It's better to spend time thinking and developing thought patterns, and then just type a little bit to jog your mind and clarify. I allow myself to write some cheap code, but the point of that is to sketch, and the sketch should be light and quick, for the same reason that artists will say to favor long, confident strokes instead of chicken-scratch markings.