I work in edtech, and the current landscape is something like 55% ChromeOS, 25% iPad, 15% Windows, 5% Mac. I might have the exact percentages wrong, but I'm pretty sure about the order. The old Mac advantage from the gifted computers is basically gone, and though a lot of primary schools do give students iPads, Windows isn't really gone gone; a lot of edtech apps are either web-based or built for Windows. You're right about Google undercutting the market with ChromeOS, though.