The issue then becomes "well why don't they just go back to a Teamspeak server? they can self host it!"
But we're forgetting there that the average person online is not a dev. The most they usually know is how to point and click on something. Which also means they usually don't know how to spin up a Linux machine/VM somewhere and install their own chat server.
Discord is popular because it lets almost anyone on Earth point and click to create a chat "server". If someone can figure out how to do that (eg cPanel), you can absolutely break their moat.
Which is kinda sad. Way back in the mid-2000s, I was playing World of Warcraft with a few people I had met in the game itself. Later on, we chipped in to rent a TeamSpeak server from a company that offered ready-made servers and we had a lot of fun. You didn’t even have to do much admin work. :(
You still don't have to do much these services still exist, even for Mumble. Their limitation is scaling. So if you want way more than just a handful of people, you either start charging everyone an entrance fee, or you cap the server.
Discord's limitation is scaling as well, to be honest. It's incredibly hard to follow a server full of tens of thousands of people. Just because something can scale in a technical sense doesn't mean it will scale in a human one.
But we're forgetting there that the average person online is not a dev. The most they usually know is how to point and click on something. Which also means they usually don't know how to spin up a Linux machine/VM somewhere and install their own chat server.
Discord is popular because it lets almost anyone on Earth point and click to create a chat "server". If someone can figure out how to do that (eg cPanel), you can absolutely break their moat.