> Surely there’s a way to keep these relationships alive outside of the system!

Yes: RSS and/or email lists. I have a blog and email client, but I also know some people who wouldn't use those things. It sucks, but that's the way things are now.

Maybe those people should know someone who doesn't use Facebook, instead of you thinking you're forced to use Facebook because they won't use something else.

We share video with grandparents, for example, you could do it by links sent over email but social-media is easier. I used to use YouTube, but Facebook upload is easier and privacy controls are easier for me.

We get to see them about twice a year because of cost and distance of travel.