Patents last 20 years, so when a new big thing gets discovered people and companies quickly patent lots of things about it. Then, 20 years later, the patents ha

Patents last 20 years, so when a new big thing gets discovered people and companies quickly patent lots of things about it. Then, 20 years later, the patents have expired and you can start to have a large amount of new interest as people are not constrained by the patents anymore.