Here's why:
* Ongoing Development: Disney World has been under continuous development since its opening in 1971. New attractions, hotels, and lands are always being added.
* No Central "Finishing Point": Unlike a single building project, there wasn't a specific goalpost for the entire resort's completion.
However, you can consider these milestones:
* October 1, 1971: Magic Kingdom, the first theme park, opened, marking the official opening of Walt Disney World.
* 1982: Epcot Center (now Epcot) opened, expanding the resort's offerings.
* 1990: Disney-MGM Studios (now Hollywood Studios) opened.
* 2001: Animal Kingdom opened, completing the four main theme parks.
Therefore, you can argue that the "completion" of Disney World was an ongoing process from 1971 onwards, with each new addition marking a significant milestone.