If most executables on your machine used Bun, then it would be a bundled shared library on your system eliminating the bulk of the 90mb executable size. Just like the shared libraries the 13043 .exe files on your computer are currently linking to.
Once again, that standard is nearly 5 years old. Microsoft has definitely continued changing their approach to OSS software. I think my favorite move posed by Microsoft that supports this is their open-sourcing of .net and working with the Mono developers to bring a better experience to all platforms.
The effects of that standard are only just hitting us now. Have they dropped the requirements for a license for exFAT yet?
As for Open Sourcing .Net, what good has come of it as of today? It looks like a move to push their own environment more than anything else. But I'll tell you what: if in 2020 the decisions Microsoft are making today prove to be for the good, then I might start think better of them. At the moment, though, they've got a lot of past to make up for.