Oh interesting-- Yeah gaming the recommendation/search algorithms is another, related explanation. Like I know someone with an Etsy store who says that various things, like running out of stock or putting your store in “vacation mode” will hurt your store’s visibility, so people find ways to game it. Totally makes sense that the same kind of thing would be going on on Amazon.

Weird that they’d allocate ad spend at the same time that they were out of stock, but like I said, the algorithms are pretty coarse and probably just not that coordinated.