It is beyond comprehension to me that people are happy about these rates. The developer only gets 25% of the sale? In order to get 50-70% of the sale you have to agree to only distribute the theme/plugin through Envato?
This is ridiculous. Some of these things are GPL, which means the end user has more distribution rights than the developer does. Maybe people just tweak something to create an exclusive version to sell on the Envato sites.
In a standard business relationship a sales person gets 10-15% commission on a sale. People think that the 30% Apple charges in the app store is a bit high.