People looking on auction sites, doing web searches and outbidding each other is them doing the work. The price remains stable because the seller only has to sp

People looking on auction sites, doing web searches and outbidding each other is them doing the work. The price remains stable because the seller only has to spend a fixed amount for the ad campaign that led the user to a particular website. Doing it your way would introduce uncertainty: what amount of time to spend, how low to bid, how many people to pay for monitoring what people want or how much computational resources to allocate to do it by machine. Investors would run the other way.