I think the main reason Apple can aggressively make it at this price is that they run their business more and more like a game console one, and they make a bit money on every App they sell to you so they can afford to sell the ipad 2 most likely at cost, plus they use Foxconn who is just above slave labor standards help to bring down the cost

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I think a bigger threat to the ipad might be the larger size Phone that are starting to appear with say 5 inch screen space, which is just enough to enjoy the web and are pritty much given away with phone contracts people will just use them as their main mobile device.
Also starting to appear are the Netbook Tablets that are pretty neat, spec wise as example
Asus EEE PC T101MT has 1.6Ghz atom, 10.1 inch mulitouch, 320gb hard drive, 2Gb ram, 7 hur battery and more for just £389.99, so they are getting pritty cheap and Windows 7 is not too bad as touch OS need more work in the app support area however.
And then their the Nintendo 3ds and PSP2 both will offer a lot more features than just gaming, like they already have done, camera and full internet ability and both will be a lot cheaper than the ipad2 so I do think the iPad2 has got it a lot tougher this time round.