Apple's not going to do it unless there's something 'killer' about it. They won't be just another player making commodity product money. Jobs requires something "WOW!" to differentiate the Apple product before he'll enter a new market.
Absolutely true. The "Me-Too" market is where low-priced clones live, and Apple has no business in that market. Their schtick is to -create- new products, and keep moving ahead of the pack. Of course, that's also what gives Apple the reputation for elitism, higher prices, and so forth. They're leading, and the leading edge is not for everyone, and costs more to ride.
As to what the "killer app" for an Apple tablet would be... well, that's what Jobs pays his "idea people" to come up with. I'm not that smart ;-)