It's not that libraries are not available, it's that they are not _standard_. Python has much healthier and more coherent community partially because everybody started out with same carefully chosen building blocks. With Lua you either build your own or bring in dependencies from libs and frameworks.
Regardless, I'm enjoying Lua more and more and it's becoming my go-to language for prototyping and exploring concepts. The code just flows more naturally than in other languages.
I think there is something else to this. Most highly productive Lua applications I've seen, been involved in, &etc., are bound to system-level libs/api's, etc. So the thing about Lua as a scripting language like Python, is that you can use it like that. But the major power of the language is when you apply it by glom'ing it into some bundle of C/C++ libraries that are, indeed, BYO-batteries...
Like, Lua is bring-your-own battery, true. For everything else, there's Penlight/luarocks, though.
