It has very little -- or perhaps nothing -- to do with "one-time points" offered to new buyers. Instead, it has much more to do with the overall growth of the
DVC system in the last five years.
BLT, which opened in August 2009, added 5.7 million points to the DVC mix. The Kidani Village portion of AKV, which also opened in 2009, added almost 5.6 million points. To date, VGF has sold over 1.7 million points since sales started in May 2013. Not only has there been a large increase in DVC points in play in the last five years, there have been tens of thousands of new Members added to the mix since the OP first joined 10 years ago. These new Members may stay at their new home resort most of the time, but some will be trying out the old resorts such as BWV, BCV, and OKW. Even if only 10% of these new members try to book an older resort, then it means demand for the old resorts increases. However, the supply of villas can't change, so they will fill up faster.
Keep in mind that the DVC system is designed to be operating at close to 100% capacity all year round. Five years ago, all resorts were filling up, but usually much later in the booking cycle. Nowadays, thanks to the internet, Disney boards like Disboards and DVCNews, the DVC Resort Availability Tool, etc., Members are much more conscious of availability and the need to book early. Thus, the resorts are filling up much earlier than in past years.
Another factor is Disney adding and expanding popular items on the calendar, causing more people to visit WDW at times that were previously slow and off-season. Food and Wine has added more days, Star Wars Weekends has added another weekend, more dates for
MNSSHP and
MVMCP, more races, etc. Even Universal's addition of Harry Potter is attracting more people to WDW. All these additions attract more people, which translates into higher demand for villas.
Although I don't have any data to support it, my gut feeling is that Aulani is actually relieving some of the booking pressure on the WDW resorts. We just returned from Aulani and we encountered quite a few WDW owners who were using their BCV, BWV, AKV, etc points at Aulani. I'll bet that if we had access to the data, we'd see that a lot more WDW points are flowing to Aulani than Aulani points flowing to WDW.