> To date the only examples of this done with a measure of effectiveness are actually entire operating system distributions backed by software like apt, yum, pkg-src, etc.

Rust achieves it. Cargo will download dependencies built for the client's desired platform.

I may be wrong but I think D does it as well.

You are right that C/C++ has a wider range of options available to it, but that is for historical reasons.

The principal benefit of a package manager like this is that it forces the packages contained therein to follow a uniform convention of platforms, build types, and options. C/C++ has been missing this for decades.