[rainbow29822]

If you're only talking in hypotheticals then they're already optional and replaceable. Someone just needs to do the work to replace them.

You're missing that these parts have to get replaced for a practical reason. Not just because someone vaguely feels it would be more fault tolerant. For example, think of some other libc that's optimized for a certain hardware. Distros that don't support that hardware would have no reason to ever use that libc. If you say all distros should support it, then your opinion is really "all distros should support this random hardware that might be rare, expensive, highly specialized, hard to develop for, etc" and now that's a much more complex and demanding task you're asking someone to do, for very little benefit.

[forgotmypw17]

I'm not saying that every distro should support every piece of software that's out there, that would be wasteful and very difficult.

What I am saying is that, ideally, every component in a distro (or any important software, really) should have at least two options, so that if one option fails for whatever reason, the user has a choice to swap it and keep working. This is already true with many components of a distribution.

This is how I am writing my application. It is not fully there yet, but I plan for every dependency to have an alternative. I also favor dependencies with long streaks of no breaking changes, having been previously affected by breaking changes in dependencies I was using.