Those that are WiFi enabled,probably. However, I do think CoAP and MQTT are relevant (and certainly used) and I included those in another blog: https://devcentral.f5.com/s/articles/what-are-these-things
Yes, authentication is/will become more important especially with devices that hold sensitive info - like health care monitors or home based gadgets. Lastly, I believe OAuth and OpenID are coming.
Thanks for the comment!!