>As a total outsider I'd have guessed that the (in retrospect justified) anticipation of large-scale civil unrest would be driving this...
There's some of that for sure but every presidential election year there's a spike due to people worrying about the possibility of more restrictive gun control laws.
The combination of the anticipation of unrest (as you mentioned), the pandemic (which generated a fear of long-term shortages of essential items, which in turn made people worry about looting and the collapse of the government), and politicians talking about new gun control laws has created a more lasting spike.
There's some of that for sure but every presidential election year there's a spike due to people worrying about the possibility of more restrictive gun control laws.
The combination of the anticipation of unrest (as you mentioned), the pandemic (which generated a fear of long-term shortages of essential items, which in turn made people worry about looting and the collapse of the government), and politicians talking about new gun control laws has created a more lasting spike.