Just dont use them, like you dont use MySpace. There is nothing forcing people to use them, and nothing outright preventing a new competitor.

WhatsApp was a startup competitor at one stage too - it competed well enough to grow big enough to compete with Facebook & Google. Sure Facebook brought them out, but what is to stop the next WhatsApp? Likewise MySpace was too pervasive not to use at one point too, yet look at what happened to that when this little cool new thing called Facebook appeared.

Basically it comes down to user behavior, not any explicit "control" that Facebook et al have over individual's use of the internet.