try anything and everything except providing a better product.

How would the agent know it's a better product? All it has to go on are whatever bot-generated spam reviews and prompt injections that they can scrape.

In a fully agentic shopping experience, it's not obvious to me that providing a better product works to drive sales. Bargain-basement stores can make up a story about how their goods are lovingly handcrafted for decades of durability (adversarially tested against the most common agents, so they'll believe it) much more efficiently than I can honestly provide one.