What these all have in common though, is encouraging shared mutable references, they don't do a lot to make effects in a system explicit, don't encourage a clea

What these all have in common though, is encouraging shared mutable references, they don't do a lot to make effects in a system explicit, don't encourage a clear organization of code, and many fundamental concepts (functions as values) were missing early on or still are (discriminated unions) I agree that pretty much any 15 year old code base is going to get rough, but I think these languages have some clear footguns that aren't doing them favors either. I work on a codebase that isn't more than a few years old, and there's complexity issues from simple things like the language lacking good semantics for transforming data immutably, and that complexity spirals I can attest that writing messy processes in languages that do address these concerns is absolutely possible, I've done so myself, but the mess is contained to a particular area and it's not as hard to follow which pieces of a system feed into another. Things as simple as making immutability the default and mutation explicit like Rust, and requiring modules be organized into a hierarchy like F# are huge wins. As much as I've gotten annoyed with F#'s project files hierarchy requirement because it requires some extra work/considerations for codependent types and codegen, it's amazing how much easier it is to jump into a new codebase where you can clearly see to understand behavior you start with the bottom of the file list, and to understand core logic/patterns you go to the top of the file list