[pdkl95]

VERY certain

    $ find /{,usr/}{,s}bin/ -maxdepth 1 -type f \
      | wc -l
    5616

    $ du -h --total --no-dereference \
      $(find /{,usr/}{,s}bin/ -maxdepth 1 -type f) \
      | tail -n 1
    1.3G    total

That's with shared libraries and debug symbols stripped. If I upgrade libc, why would I want to also waste a massive amount of time rebuilding all 5616 binaries?

Of course, even if we ignore the insane buld time, I don't have the source for some of those binaries, and in a few cases the source no longer exists. In those cases, should I be forced to only use those programs with the (buggy) versions of the libraries they were originally built with?

[scatters]

1.3 GB? It's 2021, I can read that from SSD into memory in less than the blink of an eye. Hard disk is fast and cheap enough that it's worth keeping builds around to incremental rebuild against new libraries. Also, typically tests require a build tree, and you are going to rerun tests on the relinked binaries, aren't you?