zlacker

caveat up front: I see that the point here is to talk about a nice, good thing for people to use that is useful, and I don't think that's a bad thing. I am also always looking for ways to upgrade, and I also agree that in a modern context with modern knowledge, we can do better.

However, regarding the posix skepticism - I think OP has missed (or just not mentioned) the actual thing that keeps bash/zsh from being unseated.

Industrial standards are a good thing just because they’re standards. They’re right that a redesign would be superior in terms of raw design, but this is only useful if it’s adopted widely enough so that you don’t have to context switch between two fundamental systems. I spin up a new VM somewhere and it's going to have bash. I use a tool and I expect it to follow a particular convention - having to figure out which I'm reaching for adds an amount of friction that would make most work untenable.

I like zsh but I also want something better. Type safety and robust completions would make me very happy, but if we're going to make the switch we have to do it as an industry - with a set of agreed upon interfaces and standards that are carefully thought out and built on consensus. I don't know if that's possible given the massive complexity of the state of affairs but that's what it would take.