Software evolves over time as any technology. When people invent new things, they usually launch new businesses for those inventions. They patent them. They protect their intellectual property for as long as they can.
At some point, proprietary technology becomes so prolific, that the need for agreed upon standards becomes necessary. Edison wouldn't have sold nearly as many light bulbs if they didn't standardize the size of the sockets and the shape of the two prongs, among other more important things like voltage.