> The basic problem with most package managers is that they ignore the soname mechanism. ... This allows multiple versions of a lib to live side by side, while giving the binaries the version(s) they want.

I see you've qualified your statement with "most", so you're not in the wrong, but unless I'm mistaken both Nix[1] (and NixOS) and Guix[2] handle this problem well and do it in a way which scales infinitely.

[1] https://nixos.org/nix/

[2] https://www.gnu.org/software/guix/