[icoder]

Comparable here, using mostly Zigbee (Hue, IKEA, Xiaomi and others) with Deconz RaspBee, which works great, although I do see communication issues from time to time. I have Zigbee lights and door/temp/motion sensors. I added Shelly modules behind my 'normal looking' wall switches on a local MQTT. This all comes together in a local NodeRED (on a Pi that also contains the RaspBee and runs the Deconz software and MQTT server). I use a few plugins heavily for input / output (MQTT, Deconz, etc), but I've got quite a few (reusable) function nodes as well with my own code.

Like you said, I can't see a 'normal' consumer do something comparable, locally without a technical background. It's all too fragmented, closed, clouded.