I've noticed more and more people switching to Discord and Telegram. That's normal. People aren't happy with how haphazardly Microsoft is treating Skype, and need something they can rely on. Thing is...I'm having the opposite problem.
Discord chews through system resources, and ends up making things fairly unstable. I've had outright BSoDs caused by the desktop app (a glorified web app), and I can't play any games while it's up, or else I suffer from lower framerates and outright system lag. That's when it's not taking sound and video priority away from any other application I'm running, of course. Even running it in Chrome seems to cause the same issues.
It's just... I thought Skype was a mess, then I tried Discord. I at least have some good periods with Skype, but not with Discord. It's been a pain since I first started using it.
And I'm not the only one who has problems. My mate Sildrae's desktop chugs when Discord's open. He has to close it before playing a game. Even Team Fortress 2 gets visible frame drops if they're both running.
Skype hasn't given me nearly as many problems, and that's including having the entire application unusable for a while. At least it didn't cause BSoDs. It crashed gracefully. There's nothing graceful about Discord crashing.
Of course, Skype has issues on mobile devices, and the desktop app is a pain at times. There's also the OAuth issues that keep causing hijacked accounts to appear (not to mention the actual users who don't secure their systems or accounts, and blame the platform for their own mistakes). I'll whole-heartedly admit to those issues. But that's going to happen with Discord once it really takes off.
Like Windows, Skype is a very popular platform for both normal users and businesses. It's a massive target. Black hat hackers are going to target it like crazy. Discord's growing popularity will end up causing the exact same problem, though.
Admittedly, Skype really needs to get rid of the whole OAuth thing, or at least limit it extensively. Like with Twitter, it's nothing more than a huge security headache right now, since most users click through without making sure the application they're approving won't hijack their account. But that's not going to happen without a lot more complaints.
In the end, technology just sucks from a security perspective.