1. what benefits would a statically compiled binary provide? Would it be significantly faster? Would it be easier to manage? Would it be easier to modify?
I'd guess the answers to those last 3 would be "yes, but not significantly so", "no" and "no" respectively, but that is a complete guess.
2. Would it be cross-platform?
I work in windows and macos, our CI server uses linux. Would your alternate languages/methods work across all those platforms? if not it's almost a non-starter, because we aren't going to require our devs and CI system change entirely to accommodate one smaller package.
3. how would it be installed and kept up to date?
NPM has the tooling built up for managing this. We have a bot that can ping when new versions come out after a delay, we can see install numbers and gauge when it's safe to install vs when it's brand new and still might be buggy or have un-found issues. We have CLI tooling that can parse the package.json and determine what is out of date, and in one command can update many of them and have the tests run to ensure there aren't any major breakages.
Would your method work on all platforms? How would it differ per platform? Can I install it without having to install and setup the developer tools for Go and Rust?
NPM isn't perfect, but it does a LOT of things right. Being able to `npm install` something, have it go to a local folder, then have it just run on all platforms is one that it does VERY right in my opinion. It's installed alongside node.js, and the install process is quick and painless in 99% of cases. And considering this tool is probably fast enough as-is in javascript right now, I don't think there would be any significant gains by rewriting it in some other compiled language to offset the downsides (like not being able to easily inspect and modify the code that was installed, which I have done on many occasions to find and fix bugs in 3rd party libraries).