Water supply and distribution and air conditioning were the two main forces in Southwest growth. I would also say the Central Valley Project in California was much more important than the Hoover dam. This invention changed they way people worked from its introduction. The revolution the copier began with the Haloid Corp.'s first office copier. It was similar to what people without long term memories would say about the office computer revolution.
History is always an interesting subject.
It's your list, so you get to pick the winners. This is great. This was a major turning point for Microsoft. They were able to capture the office suite software market pretty much for themselves. I just don't see it.