The Golden Age of Typography in Architecture

In the middle of the 20th century, businesses, including apartment buildings, began to be built in the style that would come to be known as Mid-Century Modern. Many of these sported beautiful typography created by an artist or the architect himself. With the reduction of detail on these modern buildings, they had became great display backgrounds for the fanciful type which sought to capture the essence of some exotic place, or convey the feel of their product in huge signs that astounded foreigners. Typography and architecture were inextricablly connected like they had never been before, or since. How did it all come about? And why did it all stop?