Discord is not popular because the technology is advanced. It got popular earlier on because the UIs for alternatives were garbage and they nailed the ease of multiple servers/channels/etc.
The entire point is that discord could be easily reproduced from a software perspective. That won’t matter thought because the users won’t be on the new network and will have no incentive to switch.
The UI is really simple to navigate. If you set up roles properly, it's really easy to automate certain things. There's a massive bot ecosystem. The voice, video chat, and screen share features are so much simpler to use than any other product I've used before. The thing that I find insane is that it's 100% free to use.
My one wish would be an easy way to handle multiple accounts.
Compare that to skype where you had to download a whole piece of software, register a new account, go to your email to activate your account, click the link for the community group chat, and then you can finally start talking in a single channel.
No amount of dev + test + management can get that technology in 500 or 5000 years. You need researchers, and they need to be smart or lucky enough to give you a competitive result.