It's difficult to ask for users to pay for a service that was always free, indeed, furthermore facebook is not growing its user base anymore. But a competitor

It's difficult to ask for users to pay for a service that was always free, indeed, furthermore facebook is not growing its user base anymore. But a competitor can emerge by providing an alternative service, for a fee, marketing it as "the service that doesn't spy on you". Now, sure, that will be a niche service, and social networks can't be niche services. The protonmail of facebook or twitter will probably never emerge.