Basically, the AUR works by downloading source code and running a build script that builds the app specifically for an Arch system, right? So why isn’t there an equivalent that works on most or all distros? Almost every time, compiling a Linux app is just running the commands that the developer tells you to, and for the uncommon times there are distro-specific differences, they’re usually listed in the README. For many userspace apps, even building across different processor architectures requires little to no change in the commands required as long as there’s a platform specific compiler. Why isn’t there a cross-distro system that can download source code and run a build script while knowing what distro-specific commands to use based on the developer’s instructions? Heck, compiling an app on the system you plan on running it on can unlock a little more performance by taking advantage of compiler optimizations for that specific processor, and it doesn’t take that long on a reasonably modern computer anyway, so why isn’t there an incentive to do it more often?
I think it is too complex. Most distributions don’t have the same Linux directory structure and different versions of libraries. So you have to ship and maintain different versions of the same library. Nix and Guix are more or less a solution, I think.
I like how Guix does it. It’s nominally a source based distro but their build farms provide binaries, so in many cases you don’t even need to build anything from source. You can also supply transformation options such as “build from this git commit” or “build with this patch” if you need it.
You can even setup your own build farm if you so desire, or if you’re using it in a research or commercial setting.