Frank Is a Partner in a Media-Buying Service, Which Is

Frank is a partner in a media-buying service, which is a type of advertising agency that specializes in the purchase of media for clients. Frank contacts major national advertisers and tries to convince them to separate the media planning and buying function from the other functions performed by their full-service advertising agencies and is having quite a bit of success. Several of his clients include manufacturers of multiple brands that have "unbundled" the media function from their various agencies-of-record and pooled the media planning and buying function together as well as several full-service advertising agencies that contract out this function to Frank's agency. Why do you think Frank's media-buying service is in high demand?