[mort96]

That should in theory be possible, yeah, though I can't imagine a great way of doing it. Do you want to add a bunch of complexity to the system's dynamic linker to make it understand "base + binary patch" dynamic libraries?

In any case, maybe you can add heaps of complexity to core OS things and save some disk space; but you still need the full patched dynamic library in memory when the process is running, so at the very least you'll end up with bloat from lots of versions of the dynamic libraries loaded in memory when processes with different versions are running...

Maybe you could tackle both of the problems by storing a base version of the dylibs and then have other dylibs which provide replacements for only the symbols which have changed between versions... but this would severely limit the kind of thing you can do without just basically having to override all symbols. And automating this process would be hard, since compiler upgrades could cause small code gen changes to a bunch of symbols whose behavior haven't changed and you wouldn't want to ship overrides for those.

In the end, while I'm sure there are things you could do to make this work (Apple has some talented engineers), I also understand why they wouldn't.