You have to understand the nature of any timeshare ownership. The developer (in this case, Disney) can sell enough points for EVERY room to be filled EVERY night of the year, less some accommodation for maintenance. In Disney's case, they sell 98% of all availability leaving that 2% (one week / year) for each room to be removed from service for upkeep.
What this means is that if EVERY owner is using the points they have purchased, EVERY room will be filled EVERY night of the year. (In reality that doesn't always happen because--believe it or not--some owners allow their points to go unused. Banking and borrowing also allows for some year-to-year variances.)
During the popular periods, rooms will fill up faster. When overall demand exceeds availability, rooms will fill up faster. And once all of the rooms are gone...they're gone.
During slower periods, some last-minute availability may remain.
In recent years, you can put the entire timeframe of late-September (when Food & Wine begins) through mid-January in high demand. Not the least bit surprising that you would find very little availability for early December on 2.5 months notice. Sorry.