The educational market doesn't focus on Linux, hell, they barely focus on Macs (disturbingly, although not surprisingly, they are all over the iOS band wagon; which is why I'll have four thousand of iPads by fall).
We have all kinds of state mandates as to what is taught and how dollars are spent (i.e. state approved vendors). Tech in education is NOT what many of us grew up with. The day of a mismashed C64/A2 lab held together with duct tape by a volunteer group of kids playing D&D every afternoon are over. Because kids cutting their teeth learning to write a program that accesses a flat text file, draw a moire pattern on the screen and other activities that teach basic concepts are over.
Primary tech is all about Lexia, Compass, First in Math and the like. It's a bunch of crap, substandard, third party software thrown onto a SMART board. It's got zero to do with life prep, it has everything to do with reinforcing the drill and test mentality while building brand loyalty.
I love Linux. I'm at my most comfortable with a fresh Debian netinstall and moving on from there. But this is education we're talking about. If it isn't "media rich", "Web 2.0 ready!", "Cloud enabled for a dynamic user experience!" or whatever bullshit catch phrase that is being spewed this week, it doesn't go anywhere.
Maybe my district is just too big. Perhaps this kind of idealism really is still possible in a small district (in which case, I need to find a new fucking job). But in my experience thus far, K-12 has turned into prestage for Corporate America. If it's not being used in the cubicle farm, it's got slim chance in the primary educational market.
It's all about numbers. Just trade profit margin for graduation percentages -- and if your numbers aren't high enough, prepare to have your funding cut.