Before the rise of github, open source projects were heavily walled gardens. Little clubs that gave you a stare when you entered the room. Github commoditized getting in touch and lowered the barrier for how much effort you have to put in or even how much you have to care before you contribute. This is gone now and you have to build trust now before you can contribute to anything.
This isn't the death of open source. It's the death of the global village were everybody can freely roam and it's easy to interact. It's the resurrection of small, social, trusted communities. I hope this spreads to all of the internet.