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?).
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.
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.
With that said, you can make some but not all packages rolling-release with apt-pinning and using stable and sid or testing which are rolling.
Bingo. That is the #1 reason (the only reason?) that a package doesn't get promoted to Testing from Unstable, because it has known bugs and they haven't been fixed. This is Debian policy manual 101.
Fix the bugs, release a new version, if no more bugs are reported on the new version for two weeks, then it gets promoted to Testing (as long as it's not a freeze?) and it will be in next Stable after the freeze is completed.
I'm on Arch and I get fresh Anki same day or week.
Installing the latest software has never been easier, especially with the AUR.
Why is this still a problem in Linux-land? Why can't we just make some but not all packages rolling-release? Making Anki rolling-release won't make the distro unstable by any sensible meaning of the word.