There are two different kinds of updates.
One is security updates and bug fixes. These need to fix the problem with the smallest change to minimize the amount of possible breakage, because the code is already vulnerable/broken in production and needs to be updated right now. These are the updates stable gets.
The other is changes and additions. They're both more likely to break things and less important to move into production the same day they become public.
You don't have to wait until testing is released as stable to run it in your test environment. You can find out about the changes the next release will have immediately, in the test environment, and thereby have plenty of time to address any issues before those changes move into production.
You definitely need different channels for high priority fixes and normal releases, stable and testing releases and all that.
But two years is impractical and Debian gets a ton of friction over it. Web browsers and maybe one or two other packages are able to carve out exceptions, because those packages are big enough for the rules to bend and no one can argue with a straight face that Debian is going to somehow muster up the manpower to do backports right.
But for everyone else who has to deal with Debian shipping ancient dependencies or upstream package maintainers who are expected to deal with bug reports from ancient versions is expected to just suck it up, because no one else is big enough and organized enough to say "hey, it's 2026, we have better ways and this has gotten nutty".
Maybe the new influx of LLM discovered security vulnerabilities will start to change the conversation, I'm curious how it'll play out.
> One is security updates and bug fixes.
That's where you're wrong. They're not one and the same.
Debian stable often defers non-security bug fixes for up to two years by playing this game.
I'm not interested in new features unless they make things actually work.
Debian stable time and again favors broken over new. Broken kernels, broken packages. At least they're stable in their brokenness.
Hence my complaint.