Some of it is because a lot of features that used to be unique in Lisp (or few other "rare" languages) became way more available in other languages - partially

Some of it is because a lot of features that used to be unique in Lisp (or few other "rare" languages) became way more available in other languages - partially thanks to Lisp&co popularising them first. Other stuff is that it tends to take some time working, and actually ending up using some of the more interesting bits, to see effect. Lots of people for example talk about macros when it comes to homoiconicity, but rarely (outside of old lisp wizards) do I see people going further to how Lisp makes it easy to build languages and compilers that are easy to debug and handle - I'm not just talking about the common idea trope of "write DSL for your program", because a) you're going to write a partial language specific to your program anyway, no matter the language, you might just obfuscate it calling them functions and types b) the easy manipulation of code and lack of parsing (and thus poof goes half the dragon book) means that writing compilers is simply... simple. And with CL's macroexpand and similar features in other lisps, it tends to be much easier to figure what is going wrong (and it's reasonably easy to add reporting of errors in compiled code down to specific form)