Economy is the main culprit. Back in the early 90's my DH and I were FL season passholders and the hotel rates you could get with these passes were really good, but then they'd come out with a FL resident rates almost every quarter which were excellent. We would go during a season (which was always off peak) and you could easily almost walk onto any ride at the parks.
This started to change around 94-95. The pass prices went up a lot (from $99 to $150)! They had a FL dining card that started at $25 and jumped up to $60. Of course, as time goes on things get more expensive, ok, but the prices of the hotel rooms almost doubled overnight and as you can see the passes and the dining card almost doubled. Those great rates for FL residents were barely available by 1996 and the passholder rates would "sell out", never heard of that in the early 90s. And, as for the MKC or now the DC, don't get me started on that one.
So, I'm convinced we're just back in that "slower economy" again because it was just the same 10 years ago that it all started the same way. I haven't seen hotel rates like DW has now in several years (not even last year at this time). Some are almost as low as they were when we were going in the early 90s (but I'm now a loyal Swan fan because during the "better years for DW" we couldn't get so much as a tiny break in their rates-meanwhile we gave them lots of business during their slowtime in the early 90s-the Swan/Dolphin are much more flexible and it's a great place to stay!).
I'm sure park attendance will be inconsistent for a while, with holiday times being busier, like this week for the July 4th holiday.