Then you'd search for "sofa with best value" and "most popular sofa". And lo and behold, the results look quite different.
Huh? Advertisers want to make as much money as possible. Consumers want to pay as little as possible for the best goods.
This is a fundamental conflict for a company that has no way to add value for the consumer.
First? google only displays ads from companies that pay them for ads. Next? they order those ads by how much money they can make from those ads.
Do you really think that how much a company is willing to pay to get a consumer to see an ad has anything to do with how good of a deal that product is? If anything, the relationship is going to be inverse. I'll pay you more for a high-margin customer than a low-margin customer.