Disney tends to look at the records from the previous year. We're seeing promos for this year's Q3 coming out because last year's attendance fell flat (no increase or decrease). Last year's Q4 attendance dropped by 4%, which means they need to increase their bookings. People booking ahead is nothing new for Disney. and typically a good indication of who will be going would be on the vacations that are already paid off. Most businesses will look at their previous fiscal year to see how they should react to the next one...they don't base decisions like this only on what's happening right now. And they also take into consideration what historically happens for the company...and in Disney's case, the fall is historically their lowest attendance time, which would also be factored in.
As far as booking ahead...people do so for various reasons. For many people, including those that can afford it without a discount, waiting until a couple of months before the trip is not doable for them. I booked back in February and am holding out for a discount. Perhaps not agreeable to you. But we simply cannot wait all the way until June to make a decision if we want to go or not. For us, we need a lot of planning. Why? Because my husband is a youth pastor and he works part time retail. The youth pastor position, in particular, needs plenty of notice when he can't be there. Also, by the time the trip comes around, our second child will be born. Our children will be watched by my parents. Because they live 12 hours from us, it's not as easy to just drop them off...we have to plan for it and so do they. So it's only fair to them to give them plenty of time, especially since September tends to be a busy month for them. So we did that. We also have two friends traveling with us and they, too, needed to notify their employers. For planning purposes, it is necessary for us to book ahead. It's much easier for us to cancel if need be, than to wait to book our trip and then not be able to do it because everything else didn't work out (such as employer notification or childcare). Of course, this is only my situation...in the past we wouldn't have done that...we waited to see if the discount was released before making a decision to book. Because of all these factors now, we just can't do that.