It's a statement of my experience in the performance achieved in practice by real developers who lack dedicated language support teams. And even the ones who enjoy dedicated language support teams. I could point to gRPC. gRPC-Java is slapping gRPC-C++ sideways. Why is that? Because when a codebase is increasingly complex, the C-style lifetime management becomes too difficult for developers to ponder, and they revert to relying on the slower features of the language platform, like reference counting smart pointers.

I think hybrid implementations, where a project enjoys the beneficial aspects of the language runtime at large, but delegates small, critical functions to other languages, makes sense. That keeps the C, C++, or Rust stuff contained to boundaries that are ponderable and doesn't let those language platforms dictate the overall architecture of the program.