It's pretty much impossible to not use Messenger these days. I stopped using Facebook, but I can't just quit Messenger unfortunately.

But it's not impossible. I've never used Messenger.

Depends on how old you are and where you live. As a college student in North America, everyone uses Messenger, nothing else. How would leaving Messenger work without shrinking your social circle to 0? In other countries, like where my family lives for example, no one uses Messenger or has heard of it — everyone is on Whatsapp. So depends on your demographics.

I'm a college student in North America and I don't use Messenger.

Coincidentally, my social circle is approximately 0. It has never previously occured to me that this may not actually be a coincidence.

I assume these college students are using messenger via their cell phones, correct?

Is it no longer possible to reach people via text or phone?

Nope, cell phones are the most popular method, but there's also a web app for Messenger (messenger.com) which makes it even more convenient.

I'm not even quite sure what Messenger is.

I quit messenger, but haven't been able to quit whatsapp yet, as it's de facto the only viable IM app in my country.

I have a clean, libre LineageOS setup on my phone, except for whatsapp.

I just sent out a message to my family's WhatsApp group and my jobs WhatsApp group that I'm moving to Telegram because of the shit with Facebook. Adding to that, that they can always call / text me.

My family has entirely moved over to Telegram, though I think they also still use WhatsApp. It doesn't bother me - change starts with yourself.