I'm told that in the early years of the National Gallery in London, attendance was allowed only in formal dress. In recent history, one art historical research library in New York required men to wear jackets and ties and women to wear dresses. I have not read this, but I believe that he discusses some of these issues in depth. Here rules of propriety and decorum were to be derived from the social and moral suasion of arts and science institutions. In fact, both the museum and the theme park, for better or worse, have redefined themselves as proselytizers of the corporate persona.
Museums still differ from theme parks.
But the presence of corporate sponsorship in each worries me because I see it as a force that will tend to erode the differences between them and may tend to modify museum missions. Corporations depend upon the promise of a stable society and depend upon dependable demographics and the expanding middle class. Museums today must create specific kinds of products in order to obtain corporate funding for future activities. These products more and more often are not the exhibits or displays, but rather the audience that has come to the museum. If that viewpoint holds sway, then I think it will not be long before we will no longer notice much of a difference between theme park and museum.