If we’re talking about Matrix as a Discord alternative, then that would mean thousands of channels, each with hundreds or thousands of users, many with constant activity.
I’m not sure if anybody actually uses Matrix at the scale of the average Discord user. Sliding sync is supposed to help, but I don’t think the Matrix architecture can realistically scale that high.
I set up their accounts
Setup is the hardest part. Syncing multiple devices and device migration are also hard. I’ll bet you’re going to act as tech support every time they get a new phone. That’s fine for your family, but it’s hardly going to scale.
The performance issues show up when dealing with large groups syncing between instances. You might just not be using it that way, but that’s what needs to work seamlessly for a viable substitute for Discord.
Matrix is notorious for its poor performance with large/numerous groups. They keep claiming to improve it, but it’s still bad.
I mean, it’s great that it works for you, but be honest: isn’t your tolerance for technological friction a bit higher than the average bear’s? People complain that Mastodon is too hard, and Matrix is ten times worse to sign up for and use.
I hate to say it, but Matrix is never going to be mainstream. Its UX is bad and it seems like it’s too bloated to fix. If I tried to get people to move from Discord to Matrix, they’d never take me seriously again. It was hard enough getting people to move from Facebook Messenger to Signal.
Or perhaps you do not understand how Discord is commonly used.
People join dozens of servers. Maybe one for every game they play, every TV show they watch, every podcast they listen to. Everything has a Discord.
Even small Discord servers have many channels. Bigger ones will have dozens or hundreds of channels.
Some servers have millions of users. Most of the servers I’m in have thousands.
Many channels are default for all users in the server.
Not sure what the mathematical average is, but this is certainly common at least, and any alternative that can’t handle this is no alternative at all.