Imagine a world where Walt never existed

[Walt Disney1955]

Some of the things you've mentioned are far-fetched, for example theme parks not existing and Universal Studios Hollywood not existing. The theme park aspect of USH naturally grew from the studio tour, and what you should really say is the Disney theme parks wouldn't exist. To say there would be no theme parks at all is unrealistic.

In regards to the Angels, they existed for around 30 years before Disney took control of them in the 90's. Before then, they were the Los Angeles Angels. There's really little to no affect.

Who's to say someone else wouldn't have come along and built good quality theme parks if Walt Disney never existed and built Disneyland?

You are right about the theme parks, they'd still exist but I wonder to what extent since Disneyland was the standard that all others have been measured by since. It isn't as if a rollercoaster wouldn't exist though, they would, and they did.

As for the baseball teams there may have been minor league teams, but there wasn't a Major League Baseball team in Los Angeles or San Fran until 1958. I am not saying this was because of Disneyland, it was because of a greedy owner in Brooklyn, but would Anaheim have grown to the point of what we see today without Disneyland? Hence, would there be the Los Angeles (formerly Anaheim) Angels of today? There is without a shadow of a doubt not a hockey team in Anaheim. That franchise was inspired by a Disney movie of all things.

I think the butterfly effect is bigger than we think culturally. Universal Studios, would they feel the need to compete the way they do without a Disneyland? Would the concept of a "Harry Potter land" even exist without Disneyland first?