While I don't think tablets will ever truly disappear, they do feel like a bit of a fad technology. In certain spaces they are incredibly useful, but they're no better than laptops for simple web browsing, especially when so many of those can fold into tablet form nowadays.
Indeed, I see tablets going the way of netbooks once augmented reality becomes more common place. When you can see a screen anywhere, why would you need a hardware device for it?
In the mean time, having a low cost solution isn't a bad idea, but tablets tend to be more premium orientated, so I'm not sure such a cheap solution with naff hardware is a great plan.