All the above reasons. Plus this bounceback offer has been out since mid October. So combine all the above with a limited amount of rooms on an offer that has been around for almost 7 months..... leads to nothing available.
Oh, and Disney has also been using booking algorithms to fill rooms. The discount might show up for a longer length of stay then what you are looking for. Especially if you only want weekends. And a holiday weekend to boot, Nov 11th is Veterans Day. Lots of people book long holiday weekends.