> And Emacs Lisp doesn't feel super accessible to most software developers under 40.
Or over 40 (I'm 42) :)
> Almost all its conventions come from a small little island, it's like marsupials in Australia, their own little parallel evolution.
This is a great analogy. And people forget that to program any system effeciently you need to know that system. Not necessarily inside-out, but good enough. A brief look at any emacs config will show you just how many weird and inconsistent things you have to contend with: major modes, minor modes, hooks, global variables, global functions, mode-specific global functions, special lists, non-special lists, and a myriad API calls and functions in between.
Wikipedia says that emacs has 10 000 (ten thousand) built-in commands [1] That's probably on par with JVM :)