It's not an issue of libraries - you're clearly right that new languages are likely to have less impressive libraries.

It's partly a matter of syntax - frankly, I can't deal with Lisp's syntactic minimalism (my problem, maybe, but there's a lot of other people like me). So there's an immediate argument for adding at least Lisp-like macros to a syntactically rich language (a task which, historically, has proved very difficult).

It's also, as suggested by henning, because there is more to meta-programming than just Lisp-esque macros.