There are two issues with this. 1. It excludes developers who have managed to find jobs that are sufficiently challenging, difficult, and interesting that their jobs keep them fully occupied, and so they simply do not have the time or energy left over to contribute to a bunch of open stuff on Github. 2. What happens after you hire someone? Do you have any policy to ensure that the job won't take too much of their tim…
I love Github, but I certainly must agree with point number 1. I work as a CTO at a start-up here in SF full-time (which means, 8am-2am). We have to a lot of developers and designers around the world which means when I'm not coding, chances are I'm managing. This leaves me very little time to contribute to my own personal projects, much less open source projects. I'd say that using Github as a resume is a great idea…
Here's an example: we use this gem called "analytical". Its configuration didn't support test vs. dev vs. production. I could have hacked on top of it - it would have added some gross code to my project. Instead I changed the original - turned out to be less code overall and didn't pollute anything in my work project. My pull request (https://github.com/jkrall/analytical/pull/17) still hasn't been accepted, but we use the fork.
I just think that the reason you're not contributing to OS is not time, it's that you choose to design within the box.