I know what you mean. When Discord was new (2015/2016) I wanted my friends to switch over from Skype (yep, we skipped the Team Speak phase because I was the only one who downloaded it). And I really hated Skype for multiple reasons. So ironically I was begging them to join Discord, highlighting what it does better but it took me until 2019 to get them all on board and by that point, Discord was huge already so they didn't join because of me but because "everyone's already there". And I am aware that Discord does a lot of marketing and that a lot of Streamers & YouTubers are using it (which I regard as passive advertising). But in the first years, due to me hyping it up and prioritizing chatting there (with people who were eager to join me) over time I managed to win more and more of them over.

I was similarly hyping up Signal when WhatsApp became unbearable for me. And again, some people were switching over because I made arguments for the switch that ultimately made them rethink. And after about 1/2 had switched almost all of the others followed too because the "nobody's there" argument didn't work anymore and fomo started kicking in. Now, I was reluctant and some people went back after they distanced themselves from the friend group but others stayed.

(I admit that I was probably very lucky in that case).

And now with Matrix, I've become more careful. I do not dislike Signal and I don't want them to think I'd leave Signal for Matrix making them move back to WhatsApp or something. And I got the fear that I may have already used the "follow me because I want you too" Joker and that they might think of me as egocentric for doing the same thing over and over again. So I just mentioned that I'll be switching, my reasons for it and that if they want to come along I'd be happy but that it is also OK if they stayed. And unsurprisingly almost noone joined me - yet. But I'm fine with that. I set up a bridge to Discord and I could do the same for WhatsApp and Signal but since you need to disable encryption I haven't yet done it (hoping that maybe one day, bots & bridges will be working for encrypted channels - if that is technically possible)...

Well in the end, if you want them to switch, you need to be persistent without being annoying and probably you need friends who are at least a little bit open to new platforms. It starts to get better once a few people join you but it's hard to get there.

Regarding the Discord part. Of course it is more convenient to stick to Discord for voice chats - I'd be lying if I said I didn't. What I tried was to be the first one to be online and inviting the other members in the channel to my Jitsi room. (Jitsi rooms launched over Element usually stay open indefinitely, so the invite link never alters). The most annoying thing is that you can't peek at who is and how many users are sitting in the meeting but the rest is pretty cool, especially that features aren't locked behind a massive paywall. Element has got a nice web widget for Jitsi rooms so Element users don't need to open a browser. But in case my friends are already in Discord I naturally join their call.

But to me, moments like Discord's servers going down are valuable opportunities to establish acceptance at least.

Anyways, getting people to switch a platform is usually an enduring process (which we Fediverse users are at least somewhat used to) but I am willing to make the first steps to break the "nobody's on there" excuse for Newton's law of inertia.