It’s rallying because there are a lot of undervalued stocks. There have been really good deals the past 2 months. And stocks are a great inflation hedge.
I don’t know why I’m being downvoted - Amazon FBA does not commingle seller inventory. The products sold by a seller are only the ones they shipped to FBA. If you request your inventory back, you will only get the ones back you sell. So if a seller sends in a bunch of counterfeit items for a listing, those are physically separated and don’t get mixed with the good inventory that is there.
There are multiple sellers for the same product and they could definitely have bad/old inventory - and they will win the buy box with the lowest price - but it’s still not commingled.
Zero traffic congestion, close to free to operate, fulfillment in minutes? Under 1 hour order delivery? There’s obviously downsides like sound and then falling out of the sky, but getting anything under 5 pounds two orders of magnitudes faster is a big deal.