The thread Chris linked to has some great discussion on the state of the art packages. With respect to your question about what’s missing: Coming from Python,

The thread Chris linked to has some great discussion on the state of the art packages. With respect to your question about what’s missing: Coming from Python, I think one might be surprised by how much less one feels the need to rely on packages in Julia. The language has some very powerful abstractions that really makes one rely less on packages than you’d expect. Julia has really inhereted a lot of great lessons from Lisp and that’s made the language an absolute treat for ‘rolling your own’. Meanwhile, some lessons from more modern languages have also made Julia much more effective at sharing your abstractions with others much easier and effective than any Lisp I’ve ever seen.