Missed one of the biggest problems: Most assume the world is simpler than it really is. Not all the world is Rust, Python, Go, C++, or whatever language you advocate. I have millions of lines of C++, I'm interested in other languages, but they needs to interoperate with our C++. When we have a C++ library that does what you want I don't want you adding a new package to do the same thing as now we need to support both - sometimes will accept that using the package is the right answer, but often we need bug compatibility.