I don't like Discord as much as the next person, but people use Discord because it's convenient. Why do people prefer Discord to IRC when the latter is free, open source, and indexable?
I use a bouncer etc but that's more than the average person should have to worry about. There is https://www.irccloud.com/ but I fear it's too little too late
Having to create an account on every IRC server is also not great.
I use and love IRC, but I get why centralised services take off. It's just a shame it's a sucky one like discord where everything just goes into a black hole.
Chats are for kids, students and unemployed.
I am an IRC lover, it's a classic platform.
But my classic IRC platform needs someone to host the server.
And it needs NickServ to add on the missing persistent usernames.
And it needs ChanServ to ensure opers don't lose control of the channel.
And it needs a bot so you can leave messages for offline users.
And it needs some sort of third-party image hosting and file hosting.
And you need something like irssi+screen if you want to see messages that arrived while you were away.
And you need to rename yourself to michaelt_afk when you're away.
And you need some way to block spammers and other unwanted bots.
And if your channel wants a browser-based option, someone's going to have to figure that out.
And you've got to take care not to reveal your IP address for DDOS by griefers.
And of course the normal ports might be blocked at work/school/college, maybe you'll need a workaround for that.
IRC has solutions for all these problems, but not particularly easy solutions. Discord/Slack/Microsoft Teams have succeeded by fixing all the weaknesses of IRC that we IRC lovers have been working around for decades.
This is it. The brain is wired to expend the least amount of energy possible. Online communities of the past were held up by the few. Those willing to do the work.
I've gone looking and there is simply no alternative with core feature parity.
In the end there is nothing special about Discord, but it does most things people want well enough.
Matrix comes the closest to fitting all the same requirements, but I've only ever managed to get one friend to regularly use it, and even then we only use it between ourselves and not to participate in federated matrix servers.
We could probably use mumble and sometime else. The screen sharing part could probably be jitsi. It's just been easier to get everybody playing our game on discord as they already have it.