That's pretty relevant comment. GitHub pull request system is great if you want to attract a bunch of script kiddies to participate on your project. For serious work, not so much.
Forking a project is a huge deal. Forking a git repository is no big deal.
Github does the former, and it encourages too-broad forks, and at the same time, discourages coordination and contribution with the original project. Nearly all forks should be short-lived and completely subsidiary to the main project.
This is why "forking" an open-source project was considered a nuclear option prior to the emergence of github.
I rarely even get pull requests from people forking my code on github, and when I do, they almost never have bothered to discuss with me prior to implementation. It's a relatively recent phenomena that is largely encouraged by the tools.