This thread is mixing two things: the distribution of free software in order to get more users, which is what the Linux distros normally do, and "distribution" of a revenue stream, which is not something that Linux distributions normally do.
If the banshee developers want to create a revenue stream from their free software project, it's not at all a given right that they can demand help with this from the distribution.
When it comes to users, it's the shared interest of the developers and the distro that as many users as possible get access to the application. But when it comes to revenue stream, they suddenly become competitors. Or rather: they become different steps in a standard sales channel: the vendor and the distributor. It's only fair that they share the revenue.
This said, it's entirely possible that the best strategy in the long run is to build your own distribution channel and get 100% of the revenue. After all, you should own your own customers, right? But then the devs or (more likely) their fanboys shouldn't complain that the distributor doesn't give them a channel for revenue generation for free.