Theoretically, you could create a Nix-Flatpak hybrid by sourcing your Bubblewrap packages/environment from the Nix store. It wouldn't be much different from how

Theoretically, you could create a Nix-Flatpak hybrid by sourcing your Bubblewrap packages/environment from the Nix store. It wouldn't be much different from how Nix handles it today, just with an additional layer of sandboxing for each environment. The problem Nix solves is the one Flatpak tries working around - how do I guarantee software builds and runs on my system? The answer turns out to be "very strictly", and Nix has done a good job of writing sane rules where it can. It's not perfect (and definitely not user-friendly today) but it has a larger package repo to work with and better support for stuff Flatpak is missing like system services. If people do want to switch to an immutable root system, I'd hope the goal is to be as modular as NixOS is someday.