The protections aren't baked into the protocol because they don't account for external real world motives of nations states which could incent them to act in a "non-economic" way according to the internal rules of the Bitcoin game.
If the attacker attempts to keep up the game of cat-and-mouse long enough they will eventually go bankrupt and will no longer be able to participate.
And this theoretical discussion completely dismisses the fact that it's nearly impossible to execute an attack like this at this stage in the game anyway.