I do not think this something you can escape by switching distro.
Namespacing is the solution, and as mentioned in the article some ditros do indeed have namespaced user repos, like Fedora's Copr. The trust model of a flat namespace user repo is completely broken when the maintaining user can change at any moment.
But let's hope we get this solved, like peer review model, vouch, or something
It is very good to be able to find build/install files for everything
There's no maintainer vetting process in nixpkgs as far as I know, anyone can own a bunch of packages. There are quality standards and it's not "here's a bunch of nix code for folks" but it's the next possible thing in the line after that.
I don't; I use Arch on 100% of my personal servers, have done so for something approaching 20 years, and don't see myself changing.
But I treat the AUR for what it is: a place where anybody can say "here's a PKGBUILD for folks" and it's on me to evaluate it on its merits.
I was legitimately asking the person upthread what other distro they felt had a better model for this kind of sharing, because they seemed to think this was a reason for Arch users to jump ship and I was curious what they thought would be the elements of a better system.