And that's it: There's simply no competition at the same level of quality. Sure, there's other chat services but none that also offer effortless voice with good noise rejection, screen sharing, media sharing, all at no extra effort and available for free. (I am aware that the latter is dependent on Discord being relatively early in a lifecycle that will invariably end in massive enshittification.)

Features like threads aren't super important to the users but being able to just conjure up a highly scalable chat community with built-in streaming support is. And yes, the network effect plays a major role as well.

I'm am member of a server that is currently evaluating jumping ship because the looming IPO promises swift enshittification like with all other social media companies. But we're also aware that moving to any other service means that new users are less likely to show up – many people already have Discord but few are willing to install a client for something they've never heard of like Matrix.

mIRC is still great to keep out pedestrians.