Julia’s type system is not particularly user-friendly. For example, it has both a “String” and a “SubString” type which cannot always be interchanged. Their language design seem to be much more concerned with execution speed than programmer productivity — Python has the balance in the opposite direction, but they’ve been gradually improving performance for years, and this is much easier to improve after the language design is set in stone, especially as more and more people add typing info to their programs.
Also, 1-indexed arrays are a major turn-off.