Some have clearly worked out. Format strings, for example, are much more appealing to me than the equivalent code. Not even getting into the crazy abilities of common lisp. (Seeing what you can accomplish just from the format string, I really wonder why it isn't more widespread.)
And regexes, despite all of the well justified jokes about them being problematic, are often much better than the code that would replace them. It is a shame there is not a BNF equivalent, sometimes.
But it seems most "inner languages" I have had the pleasure to deal with personally have not truly helped. My suspicion is that me and my colleagues just tried to do it all. Knowing when to say "not supported" in a toy language is tough. And the penalty for not doing so, is catastrophic, it seems.