Being self-hostable it can never die completely but lets face it, in most communities it's a hollowed out husk of what it used to be since Discord took off.
Any community you build inside a walled garden can be taken from you. I do think that is important to keep in mind.
The idealism of the internet in the 80s and 90s never could survive past the growth phase.
What it does technically could be replicated by current technologies.
Emojis, video streaming, screen streaming.
Discoverability by the masses is a tough problem to solve because there is really no way to monetize it. Does Discord just rely on Nitro subscriptions?
It's a gold mine of data for things like market research, ad targeting/fingerprinting, and more recently AI training.
Both are doable with modern servers and clients thanks to v3 chathistory. Ergo (server) and Goguma (mobile client) in particular make this work very nicely.