So basically, GitHub offering a service where users could charge for software, and get the source code as well? And not just a core dump, but be part of a community building up that source? ...That's a pretty solid idea.
My understanding is that that's how software distribution used to work back in the mainframe days - you'd get the source to build in your specific environment, and you could modify it to add whatever functionality you needed. Then binary distribution took over as platforms became more intercompatible.
And you still can do that—supply the source when you sell an app. But to be able to not just give your customers the source, but to give them access to a GitHub project that they can follow, and submit pull requests to, and pull new updates and so on from... plus, to not have to set up your own storefront, and manage the source permissions and whatnot. That would be a very nice feature for GitHub to have.
Heck, me too—I can think of several projects I worked on but eventually gave up on. If there was a way for me to get paid for it, still work on it, and have other people help out as well? Without having to operate my own storefront?