Amen. I've been using http://www.rapidee.com for ages though, with great satisfaction.

Does anyone have any answers why this has not changed over the years?

The profit motive. MS doesn't fix anything that doesn't make (or prevents losing) profit.

I'd assume it's some variant on: "if you need to edit / knows what the PATH environment variable is, you're likely not the sort of user who's going to be scared away by an unfriendly UI".

And you would think they would have launched a fancy editor environment editor that was easy to reach and use.

setx /?

setx path "%path%;new_dir" /m