As an initial impression: None of these example seems even remotely conducive to your idea of an optimal provider search. There can be no optimal provider of unique goods.
But, that gives enough information that I can think on your initial question, so I'll post a separate reply when something comes to mind.
Comments
What kind of marketplace? Like Ebay, Amazon, Etsy, app store, etc.?
Niche-oriented marketplaces. Etsy is a good example, along with Flippa and the Envato marketplaces.
As an initial impression: None of these example seems even remotely conducive to your idea of an optimal provider search. There can be no optimal provider of unique goods.
But, that gives enough information that I can think on your initial question, so I'll post a separate reply when something comes to mind.