I was dropped into one such system after it failed after like 20 years and learned forth on the fly while managers breathed down my neck lol. Not a fun experience, and it took about 3X as long as I thought it would take, so Forth is not my favorite language, but I do see why it was useful at the time, and as an exercise in a way of thinking about languages rather than the mode I usually operate in c/c++/rust/little javascript