I think the main reason Ruby has avoided this (like most other newer languages) is the lack of a numeric/scientific ecosystem, which is where the real mess begi

I think the main reason Ruby has avoided this (like most other newer languages) is the lack of a numeric/scientific ecosystem, which is where the real mess begins. Science code never dies (because the rewrite almost never implements everything the predecessor had, so now you need both the original tool and its "replacement"), so I have tools built from Fortran, C, C++, Tcl, Java, Python and now Rust to combine.