I don't want an explanation nor do I care, Facebook could disappear tomorrow like all the other networks before it and it wouldn't make a dent in my day.
Whether we like it or not, all three platforms are relied upon by hundreds of millions of people and businesses everyday for communication.
I'm sure the world would quickly adapt by re-adopting these things called "websites" and "email" but in the meantime, it's highly self-centered to think this "didn't matter".