Well Google still has the dominant search traffic and that's where the text ads with real intent behind them get shown and clicked on so this isn't going to do much.

And as far as people doing product searches on Amazon.com, it's not a great source of revenue for advertisers. If you want to get real sales from Amazon customer searches you need to have your products for sale either via Amazon itself or in the Amazon marketplace. They make way more money that way and place the way they place ads on their pages reflect that.

Google will retain total dominance in this area as long as a the vast majority of people use google.com for web searches.