For the general population, the user may not know to doubt reliability, nor do I think they ought to. So I think there is value in higher reliability of delivery.

For high-volume, fast-paced channels this may not be appropriate. For slower channels where people rarely post anything, you constantly asking "did I miss anything while I disconnected" might be considered spam.

> I might not want a 24/7 archive

What you may or may not want has no bearing on what the technology should be capable of providing when others may require it.

Technology can, and already has, solved these problems. If that's not your cup of tea, fine, but don't impose your own use cases on others through "but it works fine for me"-ism.