Yeah, miners will either stop mining or continue mining but hoard most of the coins they receive to wait for a higher sell price.
Or those with the most hashing power may collectively decide to invest in an altcoin before a planned 51-attack on bitcoin. Afterwards, they can pump up the alt to unprecedented levels as it fills the newly created void left by bitcoin.
You might scoff at the suggestion that the largest miners or pools would collectively decide to do such a thing. But, consider the potential fortunes to be made.