I write a lot of Rust and work on some large-ish code bases. I’ve also done Zig work and work in other languages with fast compile times.

I don’t think this is a huge moat any more. Structuring Rust codebases in a modular way to keep incremental compile times down is common. The biggest complaint about it is from people who simply don’t like the structure and want to put everything into one big package, but that’s a stylistic choice.