I don't think you understand what github is and what their goals are at all. Besides that this is bad "zero sum game" thinking.
Hint: UNIX nerds that use mutt and are perfectly happy with the standard git command-line client and using send-email or am are already served. They don't need and clearly (proven by your comment) don't want github all. Yet people clearly love github and many use the mac and windows clients. Many non-programmers are even using github for things that aren't even (entirely) code projects.
If you don't want to use pull requests or issues, just state in your README under "how to get your changes merged" and "where to log issues" what people should be doing if they want to collaborate on your project.