What benefit do you lose purchasing non
DVC timeshares resale? I know many people who purchased from eBay, a deeded timeshare (never expires, can will it to someone etc). and they are still considered a full fledged owner - each and every one of them. Plus, I didn't really receive any "extra" benefits by buying straight from the developer; except maybe the 0% interest rate.
You actually illustrated the point that DVC does depreciate just as other timeshares do. WHile not as much; they still do depreciate. I would compare a timeshare to a car. You are not going to sell the car for more than purchased it for (except of course a collector's edition).