[nowherebeen]

I think I understand your point. Landing pages work when it has direct correlation with the product.

Selling courses work because people buy because of the instructor (hence all this talk about building an audience). They can gauge how good the course is because of the instructor and the product is simple - video access.

However, building complex products or services doesn't work because customers cannot gauge anything about the product or service. The seller is not a good reference point for customers in this case.