A lot of this has to do with languages in no way designed for interoperability. There have been platforms designed for cross-language development. OpenVMS stan

A lot of this has to do with languages in no way designed for interoperability. There have been platforms designed for cross-language development. OpenVMS standardized calling conventions for interoperability. CLR does that at a VM level in low-level way. Ten15 on FLEX machine did it in high-level way. Lots of variants of languages are targeting C, JVM, etc structured in ways that make interoperability easier. Julia making using C and Python code easy is an example. Finally, there's metaprogramming tools that make all the languages DSL's interoperable via core language. Racket, Alan Kay's stuff, and sklogic's tool cone to mind. The ones having trouble are usually evolved away from cross-language development with a lot of complexity that makes it harder than it already is. Of course they're having to resort to things like ZeroMQ or whatever.