Why did physical mail volume decline as e-mail became widespread?

The decline in physical mail volume is primarily attributed to the rise of the internet and the widespread adoption of electronic mail (e-mail).1

As computer and data transmission technologies advanced during the late 20th century, they introduced electronic messaging networks that provided a direct alternative to traditional letters. While previous technological shifts—such as the transition to railroads or airplanes—helped postal services enhance their existing delivery methods, electronic media fundamentally changed how people communicate by bypassing the need for physical mail altogether.2

In response to this precipitous decline, the United States Postal Service has implemented strategies to improve its financial viability and service quality. This includes leveraging the same digital technologies that contributed to the shift toward electronic communication to provide customers with better tracking and information regarding the processing and delivery of their physical mail.1