Remember when NFTs sold for millions of dollars? 95% of the digital collectibles are now probably worthless.
(markets.businessinsider.com)
Things only have a price when two people are willing to do the transaction.
Say 99% of NFT owners have given up and mentally written off their NFTs as a complete loss. If the remaining 1% are selling at a 90% loss and some sucker is still buying at that 90% discount, the "average price" will be whatever those two agree on.
This is a bit different from physical goods because those can't just be deleted out of existence. If someone had a warehouse of beanie babies they might choose to give them away (setting the price at zero) or maybe there's some tiny value of the cloth so they sell them for a few cents per kg.