Not only that, but people continue to evolve the way they have (no pun intended) discourse. Email used to be the thing professionals and even friends out of reach did to message each other. I now use email effectively only for delivery confirmations and log in verifications. I haven't had a personal email in over a year I'd guess. People text, they whatsapp, they messenger, they telegram, but no one emails. The same with groups. A forum I have been on for decades has recently started a poll with the admins and power users of "Should we just close the forum since all the good stuff is on discord anyway".
Look at Slack's organic growth - it was great, people just started it and basically forced adoption on companies. Not so much today, because things evolved again. Discord is doing the same - people just start one, doesn't have to be official, then ultimately, it becomes official.
But you know, if your FOSS community can only survive with one specific tool, is it really a community?