I spend all day in git, but when the school asks me to install yet another online tool, I want it to be straightforward. I really don't want to spend additional 15 minutes figuring it out on the evening on top off all chores and home school etc.
The biggest thing the FSF could do is innovate on economic models that help economically support people deeply focusing full-time on making the software as easy to use, troubleshoot, and understand as possible.
There is a metaphor with Islamic finance somewhere here.
I think the free software community would get much farther if the acknowledged the realities of school districts with limited IT staffing. If you have a team of 2-4 IT people to manage hundreds or thousands of kids, you don’t want any software solution that doesn’t come with some form of tech support or at least some readily available help documentation or tutorials.
The biggest thing FSF could do is make a push for making the software as easy to use, troubleshoot, and understand as possible. Once it becomes less work (not necessarily less cost) to use free software, the change will follow organically.
Trying to petition schools to use free software on ideological grounds is a step in the wrong direction. Tie your movement to real-world incentives, not abstract ideology.