>Why can't we just make some but not all packages rolling-release?
Does that include Anki's dependencies? And if it does, does it include all other packages that depend upon Anki's dependencies?
Also, does it include thousands of other packages similar to Anki that also "won't make the distro unstable by any sensible meaning of the word"?
Don't think you'll have a "just some rolling-release packages" distro by the end of that. Unless you think this specific package is somehow deserving of special treatment by Linux distributions (why?).
I think the trick for this is to embrace distros that allow for more aggressive installation and removal of packages, plus different versions of the same package to co-exist. Like NixOS or GuixSD. Then, one doesn't need to keep the whole package tree in sync.
If the new version of Anki needs a new version of a dependency, just install the new version alongside the old one. Whatever happened when I installed this deb may also be an option.
If handling this is a huge problem, why not have all the rolling-release programs include their own dependencies. Most of us have so much storage space that, without films/games/music, we couldn't fill it even if we tried. It's cool to use minimal amounts of storage when you're on a virtualized machine on Azure/AWS, but those machines aren't used to run Anki anyway. Storage for executable usage is effectively infinite nowadays on consumer devices.
>If the new version of Anki needs a new version of a dependency, just install the new version alongside the old one.
Yes, and do that with every other package as well.
Are you even considering the implications of what you're saying? The next-to-latest version of Anki is for example in the repos of the most popular distribution. The latest version of Anki is not in the repos, and its dependencies break something in that distro.
You're free to install Anki's latest version, but there are reasons why stable distributions will not just jump on the latest version of a fairly unknown package.
Does that include Anki's dependencies? And if it does, does it include all other packages that depend upon Anki's dependencies?
Also, does it include thousands of other packages similar to Anki that also "won't make the distro unstable by any sensible meaning of the word"?
Don't think you'll have a "just some rolling-release packages" distro by the end of that. Unless you think this specific package is somehow deserving of special treatment by Linux distributions (why?).