It's not really that easy even in LLVM. Just like how real world languages don't map 1:1 to each other with all their idioms and untranslatable phrases, LLVM IR

It's not really that easy even in LLVM. Just like how real world languages don't map 1:1 to each other with all their idioms and untranslatable phrases, LLVM IR isn't a generic virtual machine. Instead, LLVM IR targets various overall architectures such as "64bit ARM processor" with "such-and-such ABI", so there is a limit to which processors the final assembly can be generated for.