The article didn't take into account savings from renting
DVC points or Disney's frequent discounts.
They used Disney's least expensive time of the year, which is when Disney typically offers its best discounts. Thus, using rack rates is deceptive.
They don't use Disney's interest rates, which are higher than the 8% they mentioned. Let's face it, the majority of PVB buyers are doing it while they are at WDW and are not shopping around for financing.
Finally, they admit they used a "conservative" 2% Maintenance Fee increase, ignoring Disney's historical average of 3.4%.
Factor these in and the breakeven moves to well past 20 years.
On the plus side, WDW DVCs have held their resale value really well compared to other timeshares. With inflation, a PVB member might be able to recover most, if not all, of their original purchase price if they sell in a decade or two, making most DVC purchases a good long-term value for those who regularly visit WDW.