Purely speculating, but there could be a feedback loop if people observed the hash rate plummeting, lost faith in the network's functioning, and selling en mass

Purely speculating, but there could be a feedback loop if people observed the hash rate plummeting, lost faith in the network's functioning, and selling en masse. The plummetting price would impact the profitability of miners, who might start pulling capacity from the network, confirming people's fears and encouraging more selling pressure.