There have been conversations about Amazon doing this on this forum and on the OSFE, I assume the NSFE as well but…
Amazon locks themselves into the BB at a low price, then high price bot’s other sellers. Amazon never has the item, and sellers who do either can’t compete for the BB or are kicked off the listing completely. The BB is therefore always out of stock, and the listing dies, even if other sellers can price low enough stay on the offer.
Walmart has started doing this. I was going through my unpublished items to try getting them active again, and most were unpublished due to Walmart’s high price bot. A few of those, I noticed, had very low reference prices, about half what these items sell for anywhere else. When I checked the listing, I noticed that the only seller was Walmart, and they were out of stock. I tried lowering my price to the reference price just to see what happened, and I was high price bot’d again. Walmart’s out of stock BB price isn’t even the reference price, it’s actually higher than the original price I was selling for in the first place.