Forth

Why is Forth so unpopular? People who are professionally using it seem to be a small close-knit group who use it independently of everybody else, is that the reason?

Or is it just too obscure for regular people? I haven't used it much myself but am amazed by it's simplicity, mainly the syntax.

Anyway I think its cool, way cooler than Lisp for ex.

Because of the Blub paradox described in http://paulgraham.com/avg.html

When, say, a Lisper looks down at less powerful languages like Visual Basic, he sees clearly that they are less powerful: they lack features like macros that he knows are immensely useful.

When, however, our Lisper looks up, at a more powerful language like Forth, he sees "weird, hairy, dangerous" features that he doesn't think are useful, because he has never used them, because his inferior language doesn't allow him to.

Lisp itself suffers from this problem somewhat, but Forth has it much worse, not only because it's of course even more powerful, but also because sussmans, stallmans and other  schumachers of this world have created an impenetrable wall of hype that points at Lisp as the Ultimately Powerful programming language.

So when a student embarks on a quest for expressive power, he is extremely likely to wind up with Lisp and never consider the uncomfortable possibility that the apparent "weirdness" of Forth (if he is ever exposed to it at all!) is produced by his own limited understanding, limited understanding of his peers and his respected teachers.