My gut feeling is that Nix is just not quite the right abstraction level. I can’t quite articulate this. And hell maybe I’m wrong.
I don’t want to configure a global environment. I just want a build system that works reliably in any environment and can cross-compile from any platform to any platform.
Nix does too damn much. All I want is a build system that doesn’t suck. And I want to run it on windows + Mac + Linux as a first class citizen. And I want to arbitrarily target any platform.
What this really comes down to is that Linux C/C++ toolchains are badly designed. Nix is a huge massive convoluted architecture to try and twist itself around that unfortunate reality.
At least that’s my spicy unpopular opinion that is probably wrong but is at least has elements of truth.
Shared Dynamic Libraries. Not to say they aren't useful. Keeping applications small, keeping security updates simple, sub linear ram scaling, yada-yada-yada, big wins cross the board, not debating that.
The pervasive link detection structure of effectively everything on GNU/Linux assumes is (more-or-less) objectively incorrect behavior in any sane security minded context. Binaries should be able to declare the interface/contract they expect (args/types/abi/exceptions/cryptographic signatures/digests). Then the runtime linker "match" against the local system. The current system is basically 2 levels of string equality checking.
Nix goes into the right direction by getting your runtime linker/elf-runtime & package manager "integrated". But this sort of just feels like putting 'lipstick on a pig' and dancing around the core issue that `foo.exe` cannot ever realize `foobar-v1.8` and `foobar-v1.7` are both installed on the same computer. Nix just manages the environment/symlinks such that `foo.exe` doesn't realize this fact.