Is this due to something inherent with Lisp? This argument also works for each aspect of Lisp that's been borrowed by other languages:

  (format t "~{~A has been around for ~D years so it seems there perhaps is something about it that doesn't fit with most programmers?~^ ~}"
          '("Structured programming" 10
            "Lexical scoping" 20
            "GC" 30
            "Closures" 40))

The last increment of power that makes Python into a Lisp seems pretty small in comparison.

Clojure does fix one of the last things holding it back: it removed "Lisp" from the name, and added a trendy "J".