"There's a world where Rust is as easy to use as C, C++, Fortran, etc. outside of cargo, but it's not an interesting use case for the Rust community to support right now for whatever reason. That's basically my point."

Yep. The Rust ecosystem is very much a product of the always-connected, move-fast-and-break-things, DevOps-CI/CD-SCRUM-Agile, horizontal scaling world... which is fine right up until the point where it needs to be used outside of that world, at which point all hell breaks loose.