Providing generic third party access is a rare case in business. Usually, data is used by third parties for a specific purpose that requires substantial domain knowledge, in which case an RDF description is probably redundant and useless.
There may be business models based on generic data but those businesses will face a serious bootstrapping problem as they will likely require either a critical mass of generic data providers or consumers, which are mutually dependent.
The bootstrapping will have to be grassroots, as it was for the original "unstructured" web, which succeeded due to the ease of publishing HTML documents, which is much simpler than publishing structured data.