What is the incentive for ad networks to suit you to whichever product best fits your needs? On price, if an ad network knew how much you needed something, why isn't their incentive to show you the the highest confidence-weighted price you'd pay rather than the absolute best deal?

e.g. if they know you absolutely need to get on a flight (dying family member or something), what is their incentive to find you the best one rather than gouging you? And if they sell that information to other groups so everyone knows to gouge you?