Disagree.
For any vacation destination, you can find an example of someone who did a budget trip and an example of someone who did an over-the-top trip. In my opinion, $2500 is low-to-moderate for a Disney trip, whereas $3500 for a beach trip is an all-the-frills included trip.
The differences:
-- Some beaches are expensive, while some are cheap. In my area, Myrtle Beach (also known as the Redneck Riviera) is super-cheap, whereas Hilton Head and Kiawah Islands are easily 3-4Xs more.
-- Some people will go out to eat "big" for every meal, while others enjoy cooking meals together leisurely as a family. Those choices will make a huge difference.
-- Some people will spend all their time on the beach, which is free. Others will feel the need to take part in paid activities, which can add up in a hurry.
So, while a beach trip can be expensive, overall the average Disney trip is going to be more expensive.
We're renting a three-bedroom condo at the beach this Thanksgiving, and our rental cost is around $800 for four nights. We'll cook, be glad to have our college daughter home, walk on the beach, visit with family who live in the general area. We'll eat out probably twice.