Although dilettantes like myself mainly play with IoT devices on Wi-Fi there is a real and growing market for industrial IoT devices that send data over Low Power Wide Area Networks (LPWAN). For example, drainage systems that must report water levels in the field (literally) and respond to instructions to turn on a water pump.
The Register has an excellent introduction to this topic.
The market is divided into unregulated and regulated spectrum. Regulated spectrum is typically provided by telecos operating cellular networks. Users of unregulated spectrum will typically provide their own base stations.
Incredibly a device powered by a few AA batteries can have a life of many years and a range of 20km in rural areas (yes kilometers).