Things officially announced than cancelled a few years later has been happening a lot since 1955/6: Walt Disney announcing Liberty Street on the Disneyland Show then it was delayed continually until it was eventually cancelled for the 1959 Tomorrowland expansion (Matterhorn/Subs/Monorail). Equatorial Africa was in the Epcot opening special, and Spain and Israel were in the guide books. The 1990s had the Disney Decade announced in TV Specials in 1990/1 and a lot of those projects cancelled (Dick Tracy, Great Muppet Movie Ride, Mt Fuji rollercoaster, Russia Pavilion, Alien Encounter @ Disneyland, Hollywood Land @ Disneyland to name a few). Since 2009 and the creation of D23 and Parks Blog, we've had the original plans for New Fantasyland (Pixie Hollow & Cinderella/Sleeping Beauty houses), Hyperion Wharf, Main Street Theater, Mary Poppins @ Epcot, PLAY! @ Epcot, Quinjet @ DCA) When it comes to DLP, the opening special advertised a Little Mermaid dark ride and Beauty and the Beast animatronic show & MGM Studios Europe. They also announced alongside Avengers Campus & Frozen a Star Wars Land, which was announced in 2018 and cancelled by 2021/2022. When you write down the list of everything announced then cancelled, it's a Big List