Docker was made because Linux sucks at running computer programs. Which is a very silly thing to be bad at. But here we are.
What has happened in more recent years is that CMake sucks ass so people have been abusing Docker and now Nix as build system. Blech.
The speaker does get it right at the end. A Bazel/Buck2 type solution is correct. An actual build system. They're abusing Nix and adding more layers to provide better caching. Sure, I guess.
If you step back and look at the final output of what needs to be produced and deployed it's not all that complicated. Especially if you get rid of the super complicated package dependency graph resolution step and simply vendor the versions of the packages you want. Which everyone should do, and a company like Anthropic should definitely do.