I understand your argument, but I think you might be overestimating the intent of the users when they're using chatgpt.

The ones killing on ads are Google, Meta, and Amazon.

I just don't see how ChatGPT will gobble those market shares - ads are increasingly tied to sales attribution, and it would require a complete shift of the market for ChatGPT to take over the role of those 3 players.

People will still try to look for content around the products they buy, or will shop for prices, or will look for feedback from other users of the product.