While transitioning from 2G to 3G only required users to get new SIM cards, the change from 3G to 4G was indeed more costly due to phones having to be built with this capability in mind. However, the need for higher speed in wireless connectivity and the major profit manufacturers made from this change showed it was all worth it.
Now, globalization is stronger than ever and effective connectivity has never been this highly demanded. Therefore, the main goal was to achieve better use of the radio spectrum in order to allow thousands of devices to be handled simultaneously by a single network without jeopardizing speed, and 5G was developed to do just that ever since it first began to be developed in 2008.
The following chart shows the main differences between 5G and its predecessor: