Ask HN: What are new devices/applications for IoT (Internet of Things)

"Capable devices increased 31% from 2016 to 8.4 billion in 2017.[4] Experts estimate that the IoT will consist of about 30 billion objects by 2020."

What is driving this growth? I want to know what other devices people are using with IoT that would lead to the projected explosion of 30 billion devices by 2020?