Secondly, how would such an archive work? Who would pay for it? How would it be safeguarded in such a way that it can be read by 'far future anthropologists' but not the people paying for the storage?
There are open repositories of the entire internet text content (common crawl). These scrapes are periodically repeated. That's orders of magnitude more data than all discord messages ever.
So technically it's not a problem making such an archive. The financing is of course always an issue, but not because the costs are large.
Secondly, GitHub is a developer platform, not a user/enjoyer platform. Issue reports are high-barrier even for devs. People get upset if you’re asking a random question, don’t check for duplicates, etc. Some people even get upset about issues without a PR.
Again, I’m all for good open alternatives but when HN is like “you just configure Gentoo and type 30 commands” we don’t stand a chance to actually win users over, gotta accept reality before we can improve it…