I actually wrote a tool a to fix exactly this asymmetry between dynamic libraries (a single object file) and static libraries (actually a bag of loose objects)

I never really advertised it, but what it does is take all the objects inside your static library, and tells the linker to make a static library that contains a single merged object.

https://github.com/tux3/armerge

The huge advantage is that with a single object, everything works just like it would for a dynamic library. You can keep a set of public symbols and hide your private symbols, so you don't have pollution issues.

Objects that aren't needed by any public symbol (recursively) are discarded properly, so unlike --whole-archive you still get the size benefits of static linking.

And all your users don't need to handle anything new or to know about a new format, at the end of the day you still just ship a regular .a static library. It just happens to contain a single object.

I think the article's suggestion of a new ET_STAT is a good idea, actually. But in the meantime the closest to that is probably to use ET_REL, a single relocatable object in a traditional ar archive.