You've got it exactly. The whole thing is modeled on the original BBC computer learning project of 30 years ago. The physical Pi device is just a platform for the delivery of educational material. People miss this because most of the commentators here don't need the educational material as they're not schoolkids or educators.

The Foundation is doing this in a highly vertically integrated way because it gives them predictability and a guarantee that the hardware meets the educational needs and also the "marketing" needs of turning kids into enthusiasts. That's why Minecraft for the Pi is important, for example.