I've been pondering something similar as a modern approach to fat binaries, basically around a table like

    CREATE TABLE functions (name TEXT, arch TEXT, body BLOB);

The advantage would be that binaries could be partially fattened, i.e. every function would have at least one implementation in some cross-platform bytecode (like WASM), and then some functions would get compiled to machine code as necessary, and then the really-performance-dependent functions would have extra rows for different combinations of CPU extensions or compiler optimization levels or whatever — and you could store all of these in the same executable instead of having a bunch of executables for each target.

As a bonus, it'd be possible to embed functions' source code into the executable directly this way, whether for development purposes (kinda like how things are sometimes done in the old-school Smalltalk and Lisp worlds) or for debugging purposes (e.g. when printing stack traces).