Agreed. The goal should be accurate market segmentation. Students, open-source devs, and hobbyists pay little or nothing, small shops pay some, and large enterprises pay more. Collaborator count seems to do that better than most metrics.
It is worth noting that GitHub organizes the Student Developer Pack[1] which comes with a Micro plan ($7 - max 5 repos). It means GitHub will offer unlimited public and private repos for 2-3 years for students who were selected.
