You forgot about a couple major difference between 2g -> 3g and 3g->3gs
the inclusion of rebate pricing and how ATT allowed people to jump up to the 3g with the rebate price.
While the biggest feature for the 3G was that, 3G bandwidth the cost of the upgrade was minimal. Where as the price to upgrade from the 3G to the 3Gs is steep and while there may be more features added to the 3Gs paying 499 for phone may be a little on the excessive side (and yes I ordered a 32gb iPhone)
the inclusion of rebate pricing and how ATT allowed people to jump up to the 3g with the rebate price.
While the biggest feature for the 3G was that, 3G bandwidth the cost of the upgrade was minimal. Where as the price to upgrade from the 3G to the 3Gs is steep and while there may be more features added to the 3Gs paying 499 for phone may be a little on the excessive side (and yes I ordered a 32gb iPhone)