I don't think it's necessary to create an ecosystem around your hardware, if all the Android-based pads are basically equivalent. It'll be more like Apple vs Microsoft in the 90s, with Google in the Microsoft role.

... though on second thoughts, I don't think the market for pad computers is anywhere near as large as the market for desktop PCs (circa 1995) or mp3 players (circa now). It's just not an "everybody needs one" sort of product.