As historical note, not all UNIXes use ELF, not only that came later in UNIX and related clones evolution, some of them like z/UNIX and Aix have gone for a PE like format, COFF.

So in those platforms you can also enjoy having private symbols by default, delayed loading on first call, and the joy of import files.

> it won't be long before someone comes up with a crazy chimera of an OS that can run DOS, Windows, Linux, BSD, and macOS binaries

TBF, the only missing part of this is that Darling isn't developed enough to run many Darwin programs; otherwise you can have that today by installing WINE+DOSBox+Darling on Linux or your pick of *BSD or illumos. (Well, running *BSD programs on other systems is a weak point, but otherwise.)

>LOL. POSIX in ucrtbase! Those are words that I never expected to see together.

There's nothing in Moxnox ucrtbase that's not also in Windows ucrtbase. open(), read(), and write() are all POSIX functions in ucrtbase.