Well, as I understand it, it's currently off the product line (at least temporarily, perhaps permanently) in Europe, and it is still available on their US website (Just checked, still there at $300).
Very sound arguments have been made in this thread about why Nokia will indeed likely always have at least 2 price points available, so it would be silly for me to rehash them. If you disagree, well, you're free to be as wrong as you like.
Oh, and don't assume the N810 will always sell for the current price. Did the price stay the same for the N800?
As for the tablets being global products, well, technically yes they are. Now: ask some of the posters here about their experiences ordering them across borders. Not as simple as you might think.