While I'm more on jwz's side in the xscreensaver issue, it's a fair bit more complex that the way you're presenting it.
You're also missing the forest for the trees - if no-one maintained xscreensaver packages for distros, then there would be considerably fewer installs of it. Centralised package management is a very powerful feature, and without it, you're reduced to the Windows style of installing software: hunt around on the web for it, try and figure out if you're getting it from the official repo, try and figure out if the download is trustworthly, install it separately, hope it doesn't sideload malware, then maintain it personally as time goes on, and maybe even suffer every second tool having it's own self-updating service phoning home and nagging you (plus you may not even be able to easily uninstall the software if the author didn't offer that option). It's easy to do that for just one bit of software, but it's a real chore to do it for all your software.
Why not get the benefit of both worlds but having centralised repositories for Snaps/Flatpaks? This way developers simply have to push their builds to it. Of course, also retain the traditional packaging model for much of the underlying system, and we seem to have hit a sweet spot between established practise and the anarchy of Windows land.
Sure. I'm a pragmatist - if that would work, I'd be happy. One major problem is fragmentation/network effects though - you'd need to get enough developers onboard to make something effectively the 'default' userspace packaging system. Major distros already have a big NIH problem with system packaging, every one having it's own system.
Packaging is a difficult problem - the 80% use case is easy to solve, but the edge cases really require elegant forethought. It also seems that every distro has a different idea of what that 20% is...
You're also missing the forest for the trees - if no-one maintained xscreensaver packages for distros, then there would be considerably fewer installs of it. Centralised package management is a very powerful feature, and without it, you're reduced to the Windows style of installing software: hunt around on the web for it, try and figure out if you're getting it from the official repo, try and figure out if the download is trustworthly, install it separately, hope it doesn't sideload malware, then maintain it personally as time goes on, and maybe even suffer every second tool having it's own self-updating service phoning home and nagging you (plus you may not even be able to easily uninstall the software if the author didn't offer that option). It's easy to do that for just one bit of software, but it's a real chore to do it for all your software.