While long-term chat histories aren't maybe that useful, the problem with IRC is that if your connection dies, you miss all the messages until the connection resumes. That is a big deal on mobile.

Bouncers are an option, but the need to use that sort of extra services will make non-technical users turn away.

Why? With chat history present, reasonable people can search for previously answered questions. Without it, if somebody joins afresh, even if their question was answered just before them, they could have no idea.

IMO it's partly because it's an inefficient platform for storing knowledge, its purpose is instant communication.

If that knowledge is actually valuable, it should be stored elsewhere, in a structured manner. But I get your point, it's better than not having any answer at all.