And what would that be? Because it is lispy? Or because of the restrictive GNU licenses?

Because nobody want to program in (((( Guile )))), to the point that even GDB disable its support as extension language.

However undesirable it appears at first, it does prevent the creation of an infinite number of new, incompatible languages. Config languages tend toward turing completeness and just become turing tarpits. That's why I'm asking about using a Lisp which is extendable to its problem domain.

Source on gdb disabling it? Just writing `gr` in gdb enters the guile repl.

It has been disable by default and is not even compiled-in anymore on all major linux distributions ( RHEL, Debian, ubuntu ).

>(gdb) gr Guile scripting is not supported in this copy of GDB.

What's your version? I'm on 8.2