Forth never really caught on... did it.
It did with me.
I wrote a PCB layout program in it on the Mac in the late 80's, I also did a lot of image processing research with it at my University. I also taught it for about 8 years at the University.
About 8 years ago I went to an access control company and a lot of there stuff was written in Forth. I was the only one in the company who could understand it.
A great little language.