No, not literally everyone, I'm in Europe, I don't use it, my family doesn't use it, my friends don't use it, nearly nobody in my city uses it, in fact most people in my entire country don't use it.
Sure, WhatsApp could roll out an update that sneakily exfiltrates your local encryption keys and/or messages any day, or might have already done so. That's the case for most apps (yes, even open source ones, since at least the Apple App Store does not allow for deterministic builds.)
It's theoretically possible to improve on that, by e.g. providing a way to double-check all client-to-server communication, but that's extremely difficult to do without at the same time weakening the encryption (since it requires either deterministic encryption and/or leaking keys via a debugging interface). I believe Threema has done something like that at some point.
Telegram however wouldn't even need to, since practically all messages are already available to them server side.
> Maybe the 'other' people you know also just use it the same way you do
I'm confused about what you're responding to here. What other people? I didn't mention anyone else. That one friend happens to be the only person I know who uses it. Or at least the only person I know who has asked me to use it.
I didn't assert that nobody else uses it. In fact, I was providing an example that not everyone has abandoned it.
