I think I was wrong. Moving to typescript has been a revelation for me, because I find I need far fewer tests to make working code. (And my code so often just works as soon as it compiles!). I can code much more fearlessly.
Rust is similar. By the time the borrow checker has sufficiently bruised my ego, my rust code often just works. And thats a joy.
What I'm hearing is that Julia is more like javascript and C, and less like typescript and rust. That in Julia you need to be more paranoid around correctness - because you can easily compile a binary that produces incorrect results. You need extensive integration tests to guard against that, because its not enough to know that two libraries work individually and compile together. They need to also be tested together or they might silently do the wrong thing.
That sounds like a bad experience. Honestly, that sounds worse than javascript. At least in javascript, type errors almost always result in instant crashes with a useful stack trace. You say testing Julia code isn't hard, but that doesn't mean I want to do it. Building a stone wall by hand isn't hard either, but I'll take my desk job every time.
Just to make sure we're on the same page though, it's perhaps worth clarifying that this particular integration issue isn't something you have to worry about every time you use two packages together (far from it), it's only in the case where you're trying to use a custom type from one package (e.g., one which replaces base Arrays or base Numbers or such) in functions from another package.