Never being opened hardly maters. It just means in mint condition. This is a mass produced consumer electronic product, not a Stradivarius. Not rare and not even the 'first edition' model. Hardly worth paying $500 more for the honour of opening the box. If you are not going to open the box then it's a brick. If you do open the box and it doesn't work then it's also a brick.
A sealed Amiga 1000? I would say that would be more like it, being the first Amiga and all, but this?
Still more power to the seller as they found someone foolish enough to pay and that means inflated prices for everyone else.