"In contemporary America, children must be trained to insatiable consumption of impulsive choice and infinite variety...So it is with the child versus the gross national product: what individual child is more important than the gross national product?"[1]

FB is the pinnacle of advertising.

Without advertising, American society could not social engineer insatiable consumerism, and therefore could not achieve infinite growth.

Big Ads is what keep the Ponzi scheme from collapsing.

[1]Culture Against Man, Chapter 3: Advertising as a Philosophical System, by Jules Henry (1963)

Because enough people in society want the services the company offers. There's almost 2.9 billion FB users in the world.