It's statistically guaranteed to fail, and IRC as a protocol spec is powerless to do anything other than shrug.
It's a social protocol.
The most obvious version of this is a netsplit, but even single users can get isolated from the network and have all of their messages dropped without realizing it until minutes later (if ever). There's no cool name for that; it's just IRC being unreliable.
Maybe unreliability is part of the charm for you, but that bug is absolutely not a feature, and not intrinsic to being a "social protocol."
You do however get informed by the server after a netsplit has occurred... and key-up retains most of what you have said recently so achieving coherency isn't difficult, although a manual task.
I did change careers to escape that...
Now in a real life situation you can mishear or fail to hear. But technology can make this better.
I might not want a 24/7 archive. Especially not for all the silly things I said in my teens.
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.
While this is certainly the initial deployment scenario, there's no reason in principle why you couldn't develop a server that natively supports that extension.
