The incentives just don't make sense to do that though. If you have enough energy and hardware to meaningfully overtake the main chain for a brief time you'd make far more money just mining Bitcoin.
There's no government in the world that would spend billions and billions of dollars to do that. It would also be the biggest advertisement for Bitcoin in it's history. "Governments are so scared of Bitcoin that they'd rather spend tens of billions of dollars to attack it than feed their citizens." Everyone Bitcoiners and non-Bitcoiners would revolt at that kind of waste.