Not the original comment poster, but control over people is probably becoming if not already worth more than the ad business.

Facebook is not a small entity, they have overthrown governments and caused civil wars in third countries already.

Facebook is fundamentally a behavioral data company. Maximizing profits entails extracting, predicting, prescribing and controlling behavior, which is in the shareholders best interest.

However, FB needs a moot around their castle, so it acts via third parties, such as Cambridge Analytica.

And even if FB would not engage in large scale behavioral influencing, then through US law, various three letter agencies can force FB to hand over the data, all the while muting the company to disclose such practices.