The reason is simple and technical. The idea behind Foundry was to take the convenience Ruby offers, and transplant it to a statically typed language. My chosen implementation path involved global type inference in every interesting aspect of it. While powerful, this technique makes writing closely-coupled, modular code hard, separate compilation impossible, and error messages become even more cryptic than those of C++.
Simply put, this is not a language I myself would use. Also, I could not find a way to get rid of global type inference which didn’t involve turning the language into a not invented here version of C#, Rust or what else.
Lessons? Don’t design a language unless you have a very good reason to. By all means, do design a language if your idea is fancy enough. And don’t use global type inference, it sucks.
Now go and check out Rust. It gets better every day.