Every magit user disagrees with you.
> and it's impractical for most working programmers to switch
This very much sounds like someone who has never even tried jj. Tell us: What makes switching impractical?
> My well-intentioned recommendation to Steve, because I've been there, is: If you want to avoid feeling like you've wasted your life in a few years on code that doesn't live up to its promise and is essentially no different than the code that already exists in Git (and Hg, Pijul, Fossil, etc.),
Is Steve even a developer for jj?
I am assuming that this new job will change that.