An common architecture for IoT is to have sensors/actuators talking to a MQTT server (a message queue). Then processing it with some rules or exposing it as a REST API. This should enable all those things as SaaS. I guess the biggest change is the MQTT server and a rules engine
I wish amazon would do a better job explaining why this new thing is better than the last new thing from amazon. Many services feel close and similar until you dig into the target use cases. Even the FAQ doesn't have a list of target use cases.