If you don't use 6, it doesn't make sense to buy 7.
it would, however, make sense to offer the 6 for sale this weekend. price is so that a person can buy your unused 6 and then pre-order the upgrade for a total cost that's less than the non-upgrade cost of 7.
you will recover some of the cost of a product you don't use. somebody else will save money on their purchase.
that's a win/win. :-)