No, the template was made with the WDW 25th anniversary celebration in 1996, castle-cake and all. "Remember the Magic" was the theme, with a song and a media blitz. They even invited radio and television stations from around the country (not just ABC, but unaffiliated local stations from all over) to broadcast from WDW for the opening of the promotion.
It ran for 18 months, then a short break before the millennium celebration, followed by "100 Years of Magic," to celebrate Walt's birthday year. That was scheduled to begin with a media blitz and kickoff on October 1, 2001; but the September 11, 2001, attacks happened, and they postponed the beginning until December 1, to coincide with Walt Disney's actual 100th birhday. That "celebration" helped salvage attendance during the travel bust after the attacks.
They learned that a "celebration" could really pump up the attendance, and have been finding a meaning for one ever since.