This is a most excellent post. With Kontakt player a developer really doesn't have to worry about distribution. The beauty of Kontakt is that the end user doesn't have to worry about machine limit. I've never had issue with machine limit with Kontakt player either.
When people develop REs and Refills to be sold in the Reason shop, they take a healthy cut, rumor has it 30% for REs, 50% for Refills. The developer doesn't worry about distribution.
I won't fork over large money that involves the Spitfire player or those other ones. VSL is the exception.