No. As price goes up, so does difficulty.
No. As difficulty goes up, price may go up. Difficulty doesn't go up based on price, it can never go down.
So when the Bitcoin exchange rate goes up (because of demand), and mining becomes insanely profitable, people don't throw more power at the network, thus increasing the difficulty? OK then. I'll stand by what I said.
What can never go down? Price? Wrong. Difficulty? Wrong.