It's definitely a piece of not just Disney history but also American history. It says a lot about ideas of progress and industry in the 20th century. When these types of performances emerged at the 1939 World's Fair, industries like GE (and GM- think Epcot's Horizons) made the argument that commercial growth and consumerism would produce a brighter national future than the types of social programs then being proposed by the Roosevelt administration. We are so much of a consumer culture now that it's easy to miss the involvement of the corporate sponsors.
OK- that's my historical reaction to the exhibit. Personally, it's one of my absolute favorite attractions...love the song (either one), love the moving theatre, love the early animatronics.