I was about to say: either stolen or illicitly acquired to have so many of these (and other Tesla parts and accessories, brand new) in stock all the time. Can you tell us where you get these parts please?
The other rational explanation is that the seller has a massive Tesla credit from either referral program (Powerwalls can convert to $5500 credits) or customer service issue and decided to “cash out” those credits by buying a ton of accessories and selling them one at a time on here.