"Wait and see" is a good approach to see whether your new electric city bus line is working or whether people prefer your website logo in red.
You can never, ever take back what became basic necessities on a nation level while being even remotely democratic. Once people have it, they won't give it back.
And you seriously think Facebook is to be given any such power, even after Cambridge Analytica? We're talking about currency, and billions of people. Lifes are very much at stake.
But sure, let's wait until Facebook uses Big financial data to get some populist party manipulated into power and a mere few thousand people die from the consequences, than be all enraged on reddit for a week and unable to change anything? I'll keep my typical German mindset, thanks