I don't want to beat this one to death, but just wanted to put another Engineers' stamp on it... Bear with me as I nerd out on this.
As part of the design for any large foundation, be it for a building, bridge or large ride, soil borings are made to determine the soil properties at different depths. In a case like this, one large foundation would only require one or two borings to be pretty accurate, unlike a long bridge that may have nearly 100.
A tall structure doesn't necessarily need deeper piles, it all depends on the soil. Looking at old pictures from Dragster construction, I believe each leg of the tower is on one large spread footing. Most, if not all of the foundations for Cheetah Hunt are spread footings as well. I've worked on quite a few foundations in the Tampa area that only consist of 30'x30' spread footings, some supporting upwards of 2.1 million pounds.
That's not to say piles couldn't be necessary. Florida gets pretty unique in terms of Geotechnical Engineering, as we usually don't have any rock layer to bear on, usually just a very dense sand layer. The really long piles have most of their capacity from the friction between the soil and the surface area of a pile. Take the bridge on SR 408 over Lake Underhill by the executive airport for example. That lake is really just a sinkhole. The bridge is supported on piles 30" square nearly 200 feet in depth, the longest in the state of Florida. The first 100 feet of soil is so weak, it's considered to add no capacity to the pile.
I've seen many foundations in quite a few states - you could put me down as surprised if the foundation became cost prohibitive.