how do you see Nix being affected or not by newer package management systems with built-in sandboxing and layering, such as OCI container images on the server side or flatpak on the desktop side?
There has also been sharing of ideas and collaboration between things us and bazel/buck/spack/etc. I think it is clear that we are all moving towards a similar end state, that often looks very much like Nix, or a re-invention of it.
For things like OCI, Nix predates it, but we should start to re-use the standard. The Tvix group is exploring this and I'd suspect our sandboxing will be OCI at some point. For outputs; we make it easy to convert a Nix package into an equivalent container. Things like flatpack,AppImage,Snap should also be easy for people to output (i'm trying to collect these "transformers"/"bundlers" here: https://github.com/NixOS/bundlers).