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No you've forgotten smooth's point, because the 51% attack requires ongoing hashrate expended by the attacker indefinitely. The network eventually heals when the attacker stops.
The 100X attack is death star. The chain doesn't heal (even after the attacker has stopped mining) without external intervention of a fork, because the difficulty is in the stratosphere so thus no block is ever created again (or not for a long, long time such as years).
So does the 100x attack since the attacker has to maintain the attack for a period longer than the number to blocks used by the difficulty algorithm to calculate the change in difficulty. So my point is why would the attacker not just fork the coin and set the difficulty to some insane high value?
There is a huge difference between forking the protocol with 51% hashrate and adhering to the protocol with 100X hashrate (both being ways to set a stratospheric difficulty level).
In the former case, honest miners will ignore the fork. In the latter case, they can't do anything.
ArticMine you are a physicist and I am a programmer for 37 years. I will be more skilled at my field and you will be more expert at yours.