[Expez]

You're absolutely correct. The 51% example that you bring up would be an undesirable outcome (from our PoV), but the incentives are in place to ensure that it is extremely unlikely to ever happen.

Distributed consensus is a non-trivial problem, and for sure certain tradeoffs were made by Satoshi to make it both distributed and permission-less.

Unless you want a benevolent dictator of some sort all you can do is set up a system that's robust from a game theory perspective.