Answer:
Cell phones
Step-by-step explanation:
If we go back a few years in time, a little over 30 years actually, cell phones were not smart and you could only talk with them. Actually, they were so big and heavy, that you could use them as hammers also. Motorola's first cell phone was as big as a shoe box and weighted around 2.5 pounds. Back then cell phones were expensive and very few people used them.
Fast forward a few years and smaller cell phones appear and 2G technology arrives. You could use a cell phone to call or message someone else. As cell phones got cheaper, more and more people started to use them and companies like AT&T started to collapse and you couldn't get a decent signal anywhere.
But cell phones would continue to improve and 3G was developed in order to satisfy the growing number of consumers. AT&Ts signal was still terrible. Blackberry came and phones started to get smarter. But as cell phones got smarter, more people wanted them. Then came Steve Jobs with the iPhone and demand grew so much that all the companies' systems collapsed (now all were as bad as AT&T).
That led to the introduction of 4G technology, but even before 4G technology is available everywhere, 5G technology has been developed. Finally, 5G technology is available in all the US (this year AT&T managed to do so, although Verizon did it earlier). But in other countries, 5G technology is already becoming obsolete and 6G is soon to be the standard.
Our everyday use of smart devices has forced technological advances to speed up. It took about 15 years for 2G to arrive, and then it took about 10 for 3G to be available. But in less than 15 years other countries have gone from 3G to 6G (China has already launched its 6G satellites which will start providing that technology).