You haven't seen those devices because Apple's brand-name competitors are choosing to enter the high value markets first. Anything with a recurring data contract brings in far more money.

And Google itself would rather make the devices and the contracts cheaper, so that the users can spend more time online using Google products. They'd rather replace a kids iPod (inc. Touch) with an always net-enabled "phone" if possible.

But away from the headlines there's been generic, wifi-only Tegra2 tablets on the market for a couple of months now at half the iPad price. Not only does the Tegra2 beat iPad hardware, it's in line with the rumours for iPad 2 hardware. So the magical Apple hardware efficiency and price competitiveness doesn't really add up.

Note these generic tablets have plastic bodies, screens with poor viewing angles and non-tablet Android often without market access or official Tegra2-optimised Flash out of the box, so they're a tinkerer's delight rather than an iPad killer right now, but that's a separate issue from the power and cost of the hardware.