It's pretty uncommon for there to be public parking within miles of a theme park. Especially one the size of Disneyworld.
Maybe I'm just poorly traveled, but I've been to several theme parks including all the one's here in CA and there are plenty of places to park along the streets that border the park.
Perhaps some people here have just not had to work a "regular" job in a while (either self employed or employed in fields where things aren't quite the same), but in most cities in this country you are pretty much just going to have to drive to work.
Sure you have to drive to work. However if we are going to talk about "averages" here, an overwhelming majority of people work in areas that have accessible parking available to them. This is guaranteed if you work in a downtown area. Its also very easy to find if your business is in a more suburban setting and probably free to boot.
No doubt that there will be people that face greater hardships than others. However thats just the nature of rights. They are obstructions to the actions of others.