I was referring to technical solutions, not fines or regulatory measures. For example, before Bitcoin cryptographers published a mountain of research on designing secure and anonymous electronic payments, but relied on a central bank that issued and redeemed the money. The bank was constrained mathematically so that it could not link user transactions, unless some subset of users had cheated in some way (double spending). So there was a central party but certain forms of abuse were impossible, and those systems were overwhelmingly more efficient than Bitcoin or even a proof-of-stake approach ever could be (this is because transactions are "truly" peer-to-peer, meaning that only two parties do any work at all when a payment is made or when money is withdrawn from or deposited with the bank; moreover the work required to perform transactions amounts to verifying a few signatures/NIZKs). Another example is the use of oblivious RAM for secure cloud storage, which both protects user data and ensures that "most" of the access pattern (everything but the number blocks of data a user has accessed) remains private. There are also many examples of real-world deployments of secure multiparty computation that limit abuse by large/centralized parties in various ways while still allowing those parties to operate and even expand their business (without having to collect more user data than they already collect).