Adams is describing how marketing (tries to) work. Marketing seeks to identify customers. In a manner of consideration, Adams is seeking to acquire better and more targeted search results, or skills in searching for products or services. Google Adwords tries to offers something close. But the Googlers are not very good at this level of targeting. (Yet?) As for specifically contacting buyers, that's expensive for comm…
The thing is that the customer can afford a few small one-to-one transactions. It's not hard for them. However, the supplier likely wouldn't be able to afford the costs. Lots of one-to-one transactions don't scale.