To be charitable, I'm assuming they're working on the idea that with RoL, coming on line in the next few weeks, Star Wars shortly afterwards, and Epcot seeing a new, high demand attraction, and a plussing of an existing one, that guests will be more dispersed across the parks, especially during evening show hours. That may also be driving a sense that many guests will be opting for later starts as they have a wider variety of 'must see' shows in the evening.
Some of it of course is just thoughtless penny pinching.