High caliber people need to get paid. Sun invested heavily in zfs. No one (and by that I mean organizations with resources) is really giving btrfs much attention.
I'm in my 30s and still in school plus other venues where Facebook is used "to get work done". Most of my family and in-laws are overseas (in different parts). I dispute your claims. I'm not convinced that fundamentally usage of Facebook is different in different parts of the world. The memes are different etc etc. But I don't see how it is a critical piece of infrastructure anywhere.
I was in college when Facebook didn't exist and then it did - so I've experienced both realities. Somehow I lived. It's very useful now and students gravitate to it because it is pervasive and easy enough. Fine. But if it disappeared tomorrow.. life would go on pretty much as usual. People would find other ways to communicate.
You bloviate but your comment is without any real substance or examples.. just hand wavy people do different things with it. Still doesn't change the fact that it is just another ad and meme delivery platform that happens to have some other useful features with less pervasive but usable substitutes. School events and class.. yeah be a bit of a pita for a bit.. but there other ways if it came to that.
I enjoy that you take an unsubstantiated statement to conclude something is patently false. What's your evidence that a weak and dilute acid like vinegar is going to cause corneal damage?