esbuild is written in Go, which has similar "probably quite fast and easy to install" properties to Rust.
Compare that to the expected experience if it was written in C++ or JavaScript or Python or Java or ... All of those are either likely to be slow or painful to use.
One of the reasons few people do that is because the build process becomes much more complicated. It's also much more complicated to do any sort of dynamic loading which is not terribly uncommon.
Compare that to the expected experience if it was written in C++ or JavaScript or Python or Java or ... All of those are either likely to be slow or painful to use.