> But to flip this around, let's say you want to use this third party in some other "modern" language how would this become better?. Clearly if someone hadn't done the work to package in vcpkg/conan you can expect it wouldn't exist in pip/cargo/npm either. So if you had a bad time in C++, you would have a dramatically worse time in other languages.

Err, no?

In case of Rust usually there is really no work that's necessary to package it and upload. You just type `cargo publish` and you're done (after filling out metadata in Cargo.toml). Even if someone wouldn't upload it to crates.io as a Rust crate you can just add a single line to your Cargo.toml:

    package_name = { git = "https://github.com/user/repo", rev = "revision" }

and you're done, you can use it as a dependency.