Because markets move quicker than they did in the 18th century. These bubbles have progressively grown and collapsed quicker and quicker with the introduction o

Because markets move quicker than they did in the 18th century. These bubbles have progressively grown and collapsed quicker and quicker with the introduction of railways, telegraphs, phones, improvements in printing presses, radio, television and finally the Internet. The pattern is still the same. You can look at Railway Mania, the Oil boom of the mid 1800s, the Florida property boom, the airline boom of the early 20th century and the Dot Com boom of the late 90s for reference if you want and you can see that they become progressively quicker.