One would assume the same way they survived in the era without any Facebook.
Now, in a world where Facebook exists, we should probably consider the effect that its particular flow of information has on society. Keep in mind: this is the same company caught running A/B tests on its users without their knowledge on whether running "happy" or "sad" stories had effect on their observable behavior.
The public should probably care about what effect Facebook has on it, because Facebook cares about what effect it has on the public.
In an ideal world, which we do not live in.
> They're still going to
... and that's what makes the question of the role of Twitter and Facebook in modern society so dang complicated.