Postcards
The decline in postcard sales is not the most startling item on this list. Once upon a time, 20 million postcards were sold every year. Today, there are only about 5 million sold. But the reason why everyone is less likely to receive postcards might come as a surprise.
Postcards were already on their way out with the creation of email. Later, with the introduction of things like Facebook and Instagram, the Internet had basically become a widely circulated postcard. Why take the time and money to send a physical letter when you can just post a virtual message? Now, postcards are used more for decoration than for correspondence.