I used to think a Kindle was an overpriced single-trick pony. Then Amazon sold it for $100 and change, now I take it everywhere, home, gym, plane.
People will buy IPads because they are cool, sexy, easy to use, and useful. People don't care how much they cost.
For non Apple tablets, they just have to be cheap enough for people to say, "why not", and then they will buy them. I don't understand why the other manufacturers don't "get it" yet. They can't compete at anything close to Apple's price.
-W