Walt's studio didn't invent animation, but they did take it to the next few levels and make it a respectable art form. Sure, cartoon creations like Felix the Cat and Popeye the Sailor would have happened regardless, but I highly doubt anyone would have had the courage to create full length films if Walt hadn't done it first.
During the mid 30's, Hollywood started grumbling about a crazy idea that was being brought forth by Walt's studio. A full length feature was in the works. Walt had to take out loans and seek out investors to finance this dream of his. That kind of action doesn't happen without creating a buzz around town. In those days, the only animation being shown were the 6 minute shorts playing before the films, between news reels. It was popular thought that no one would want to sit still for a full length animated film. It was also suggested that watching a full length film would cause blindness. The film was dubbed "Walt's Folly" and it was believed it would be Walt's undoing.
Snow White and the Seven Dwarfs released at the Graumans Chinese Theater on December 23, 1937 to great success, both critically as well as financially. By the end of the film's release, the studio raked in a whopping $8 million profit. That was Great Depression money. With the profits, Walt built a new studio in Burbank in which the company still resides. What became of the neigh sayers who felt Walt's film would fail? They publicly requested a sequel. The headlines wrote, "More Dwarfs". Go figure, right?