Think about what happened and you'll have your answer...
We saw a run on inventory of AR's, so production went through the roof. Then we saw an eddy behind the boom - a little faster occurring than any of us thought it would be, and inventory went through the roof. Retailers were choking on a high AR inventory for a few years, trickling them out here and there. Now they're back to a manageable inventory volume, and demand is relatively steady, and relatively low. Why hold 20 AR's on the shelf when you're only selling 2 a week?
There was also a greater trend (same thing we saw a couple decades ago in the last great AR boom) where more and more folks re-directed to building their own or having one built rather than buying a factory model off of the shelf. We saw the same trend in the last boom when folks started building their own - retailers who carried AR inventory (much much less common than now, of course) ended up with very dusty rifles on the shelves, even though consumers were still buying new-to-them AR's - but building them instead.
I don't believe we're seeing any inventory reduction due to panic buying at any significant scale as we have seen in the last few years. What we're seeing are retailers going back to a JITD methodology and not getting ahead of themselves. It's just an election - even though it's only every 4yrs, it's not an uncommon event - PLUS, the average American doesn't vote anyway, so if you tie in the scale of political motivation comparison to the scale of the emotional knee-jerk response to a national-newsworthy mass-killing, this just doesn't compete. When a mass-murder event happens, politicians have the opportunity to feed on a single-issue national emotion to drive a single-issue legislative campaign. In a presidential campaign, there's a lot more on the table, and consumers recognize that fact.
Am I buying more AR's, more lowers, or more parts today in preparation for an election? No. Would I be buying the same in preparation for an election if I wasn't already well supplied? No. Do I keep myself well inventoried on ammunition, loading supplies, and firearms to be prepared for any political or legislative eventuality? Yes. An election year shouldn't be your reminder - a responsible citizen should be prepared to defend themselves against any enemy to the American way of life, foreign or domestic, regardless of which party is in office.