"How do you use search to introduce the right buyers to the right sellers when it's not a frequent transaction of a commodity?" The responsibility is the sellers! . We invented Persuasion Architecture to present the answers the buyer seeks. Chapters 19-21 of "Waiting For Your Cat to Bark" tell you how...
Planning Persuasion Scenarios is the core of Persuasion Architecture and it ensures that that seller will leave a relevant scent of information based on answering each buyer's questions, addressing each need, each motivation, and even each buying preference. Whether the sale is complex or simple, whether the buyer is late or early in the process, whether the buyer is knowledgeable or ignorant, high price point or low, it doesn't matter. The seller must account for each customer segment and each angle of entry that customers may take as the need for your product arises.
It isn't easy, it's a lot of work. Every touchpoint, every page, every keyword, every marketing communication must be accounted for . Persuasion Architecture handles this complexity.
In today's landscape the seller is the only one with papable incentive to do the work of Persuasion Scenario planning, so it is unlikely that search or any other middle party will get too involved in solving this. And sellers selling these types of transactions simply can't afford to wait for search technology to solve this problem for them.
Read Seth Godin's entire post.