The massive nuance you are missing is that IRC had a default expectation of being ephemeral in nature. Sure you might use IRC for chatting and have some bots around that - but typically your long term storage of information would have been handled in something like a forum, website, email list, file repository, etc - so that even if an individual IRC server went down it wasn't a big deal to move along. IRC was/is less a platform and more a protocol.
Discord on the other hand does everything IRC does but people have made it take the place of forums, blogs, file repos, etc etc. All this information is locked up in a platform that can't be searched or often even accessed without signing up for the platform. Unlike IRC however Discord is not a protocol that others can tie into - it's a platform and they can/do actively lock people out of it.