Why so many AQ Hurricane PC's for sale?

Could be counterfeit. Many fakes have been available from China for major brands for quite some time. This has been a thing for at least a couple years.

For instance the Nordost Odin 2 interconnect (which I have tested in my system, $17K) was available from China for $100. I was interested in how good a fake they were so I bought a pair. They looked exactly like the real thing... except the wood block on each cable was made from a different wood, loose and not as well made as the real thing. If you knew nothing about there being fakes, I don't know how anyone would figure out it was a fake. it out... no it did not sound as good. 

Careful buying used AQ especiially the storm and higher lines. Lots of fakes. 
TMR usually has preowned hurricanes. I’ve bought a few from them. 
I am not a fan of AQ Thunder, Tornado and Hurricane they just don’t sound right to me but I know @ghdprentice enjoys them. 
If you’re looking for big bass and dark sound, although with pretty nice mids, give it a shot. I like the Nordost stuff - Frey 2 is great on amps and digital. 

I realized my post didn’t really answer your question.
AQ is a major brand. They sell a lot of cables and you see the quantities on a used a used market proportional to new sales over time plus people just rotate cables. Sprinkle that with fakes.

Cables are very system dependent. I sold my hurricane's after comparing them directly to Clarity Audio Vortex power cords. The Vortex's are more open and detailed compared to the hurricane's in my system. I didn't realize how dark the hurricane's sound until I compared them to the Vortex.