That's because the design of the language is so strongly skewed towards unification and search. It's great as a database / ruleset query language, for example,

That's because the design of the language is so strongly skewed towards unification and search. It's great as a database / ruleset query language, for example, but it's not as general-purpose as e.g. Lisp or ML. It makes a lot of sense to embed it in something else. (I wouldn't try to write a web server in Make, either, but Make is quite useful in its specific domain.)