Consider the problem of predicting an agent's binary choice. If an agent follows a strategy of always choosing the opposite of what the algorithm predicts, then the algorithm's prediction will always be incorrect. A "true future predicting algorithm" cannot correctly predict the actions of certain kinds of agents, as long as those agents can observe the prediction.
People are not their governments. Viewing competing governments as competition between their countries - I think that is propaganda. The US government violates the privacy of US people through mass surveillance. Now it is competing for control over social media. Yet the goal of mass surveillance of US people, which harms US people, is justified in terms of US interests.
During the cold war all sorts of things were justified because they made sense from the perspective of US (governmental) interests. The Vietnam war, the Mujahideen, the toppling of free and democratic governments. In a "realist" framework, the ends justify the means. The "ends" and "means" here are considered from the point of view of the statesman.
When the world is viewed as a chessboard between competing nations, human beings outside the decision making centers suffer - we are reduced to being expendable resources, collateral damage, in the pursuit of "national" interests.
The money is there, it just mostly resides in the hands of the few. The mean net worth of an American household is almost $700,000 - that's total net worth of all households, divided by number of households.
I think it's because of the common assumption that the system that controls your data must also house the application that interacts with this data. When decentralized applications finally arrive (the inklings are already here) users won't be forced into this false choice. In that sense, companies like Google and Facebook are behind the curve, and don't really represent technological "advancement", but rather a social shift that has legitimized itself by falsely presenting itself as inevitable.
I kind of think of imminent battle between decentralized/centralized as analogous to the Linux/Windows wars of yesterday. Over the short term you're probably right that centralized services will win. But because decentralized services yield control of your data, they have the potential to be so much better for the consumer than centralized services.