The analyst firm ABI sees LPWAN’s encroaching on short range wireless technologies — which you may know is not exactly a new idea. The easy question is: why would you pick short range technologies like Thread or ZigBee if you could get better range/signal propagation more or less for free using an LPWAN technology?
Bluetooth has a great chokehold on Personal Area Networks and while I have never seen WiFi as a viable solution for low power devices it dominates in mains-powered LAN connectivity. The remaining collage of short range wireless technologies, many operating at 2.4 GHz, remain ripe for disruption.
With luck, we may be approaching a more “unified” networking vision for the IoT that allows us deploy a more limited number (not just one!) of wireless radio technologies in order to address both long range (WAN) and shorter range (LAN) use cases. Not only does this make IoT LAN’s better, it addresses use cases that straddle the LAN/WAN “dividing” line or that may transition between indoor (e.g. warehouse) and outdoor (wide area asset tracking) use cases.
This encroachment by LPWAN’s to me is inevitable and will happen more suddenly than most of us expect. You could say it’s a “new IoT” that is replacing years-old IoT technologies that were designed in a different era.