I love GH, but I only use it for my public projects. Limiting private repos ($200 for 125?) seems insane to me, and it will drive people to make public items that shouldn't be.
For any private projects, or ones involving clients, I use BitBucket and make all repos private. It's a difference of $190 for me (I use the $10/mth plan with BB and host well over 125 private repos).
But that's not really github's fault for people having public repos. For $20/month I can setup a VPS with my own source code hosting service (full management like gitlab) and host all the repos I want. I get people love the features of github - but they never really use them.
I would say people use public repos on github because they are lazy. And when people get nailed for uploading their Amazon AWS keys - they should really think about an alternative solution for their git repo needs.