LoRa gets part of its efficiency from fairly brutal sleeping, to the point where the radio would only get turned on to transmit when sensor data meaningfully changed or some (weeks) timeout comes up to say "yes, I'm still alive".

Also, it's range being longer than normal mobile phone cellular radio allows getting away with sparingly-positioned gateways.

Also it's not truly star, but rather gateways vs. nodes (at least with the popular LoRaWAN stuff). All gateways that pick up a node's transmission will report it to central servers.