Then the world will be a pretty dull place. There would be no theme park that will revolutionize the amusement park industry. Many cartoon shorts and animated films that changed the world will not be there. Lack of inspiration and imagination and no recreated films based on the Grimm fairy tales. If there is no Disney, then those animated films based on those stories will be much darker in tone, violent, true to the stories, and a sadder story.
Also, many amusement parks will be the same. Though, some will be clean and most is still ghetto and dirty, but that's not the case. Since Walt Disney himself was inspired from another theme park in the Netherlands called Efteling which led to the basis of Disneyland as well asTivoli Gardens in Denmark. Both of them of course are older than Disneyland, but in an alternate reality, Efteling will be the Disneyland, the theme park that changed the world and inspired millions. Those two parks are clean and well kempt as well as having attractions that is similar to Disney.
But, the real question is: What if there is no Walt Disney and Disneyland?