To offer some additional thoughts. First, It's very likely that late in the contract it will not be worth closing costs to sell it but I think that time will be the last 2-3 years, not 7-10 years. However, it's entirely possible that the fees will get high enough that DVC is not worth closing costs earlier. If the current approach of having resale buyers overpay on maint fees is still in effect, it may be a little sooner. There is also likely to be an over supply at that time so that may further reduced prices. I wouldn't be surprised for DVC to take back points late in the RTU just to keep the price from being too low, although only if they are still in active sales. People have to realize that this is more than just an economic issue. There has to be enough savings and benefit for one to act and often that's as much an emotional issue as a mathematical one which is most certainly going to work against sellers.
UY will also have some effect on sales late. The other factor is HOW DVC decides to handle the fact that there are NOT enough villas and time to accommodate all points in all UY the last 2-3 years. So not all points will be able to be used late in the game by the extension date. Likely possibilities include a lottery, voluntary relinquishment with no fees on the points given up and a free for all with a lot of points expiring unused. It's also a certainty that banking will be suspended late, likely the last 3 years of the contract. These decisions, once known, will have an effect on any value and it's likely that just the uncertainty of these issues will have an effect as well.
I go back and forth on the extensions. I do think they likely will at some point but I don't know how or if it'll be worth it, it very well may not be, OKW clearly wasn't as offered. The only affects on taxes are for deductions for the real estate taxes and for income if you rent it (minus fees and other expenses). While technically there are limits on yearly increases, the recent reallocations have proven what I said all along, this really isn't a limitation, you just do it over 2 or more years if you need more.
Other non-Disney timeshares can be purchased for $1.00 so anything can happen to the price.
Bill
Some yes, some no. The reality is that market forces don't work all that well in timeshare sales overall but Disney is more known and in some ways, an entity unto itself. I think market forces work better for DVC than most, same for Marriott to a degree. However, it's very possible that DVC will be in this boat at some point as well, esp late in the RTU expiration.