Films for the theater were being created and projected long before TV became popular in the home. In the late 1920s, filmmakers began looking for bigger and better ways to display the full scale of their creations. This is evident in the various different prototypes of cameras, projectors, and sound equipment that were being developed at the time. When the Great Depression swept the nation, however, many of those ambitions to upgrade theaters and film technology were put aside until the 1950s when, in the wake of WWII, Hollywood (and television) experienced a boom.
This is where many people get confused. In the 1950s, individuals began to purchase televisions for their homes. The argument goes that the film industry was so pressured by a downturn of business in the movie theaters, that they created new film formats, not compatible with standard TV displays, to lure viewers back to the big screen. There is some truth to those claims, as theater technology was vastly outdated by 1952, but the evolution of widescreen at the same time as the rise of television is likely more coincidence and economic timing than anything.
The truth is...in 1952, a film was released called "This Is Cinerama," which introduced a big-picture experience only rivaled by the likes of Citizen Kane, a 1941 production that revolutionized film technology several years ahead of its time. "This Is Cinerama" used a newly developed system of capturing images with three 35mm cameras and then projecting them side by side onto a massive, arced screen. It also used a new sound technology called Stereophonic, which produced highly realistic, three dimensional sound. The film industry and audiences alike were rocked by the huge sounds and epic magnitude of the giant screens as they scrambled to fit the new format. Many people will recognize Citizen Kane as one of the earliest, and perhaps the most famous, films to be produced for the "wide" screen. As money flowed into the industry, filmmakers continued to break away from the Academy Standard in an effort to produce more magnificent and artistic cinematography.