The real IoT devices
The real contenders are super-cheap Wi-Fi devices based on the ESP8266 chipset. You can have cerified $10 behind-the-wallswitch devices like the Shelly 1 that use a cloud service but can also instead talk to a local MQTT broker.
You can even flash an open source firmware (Tasmota) onto them.
No vendor lock-in, no royalties. I suppose Amazon could fork Tasmota so that it works with the AWS services discussed here.