Zigbee was designed to make it very inexpensive in terms of both money and energy to deploy a large network of battery operated devices without requiring human intervention to rebuild the network every time one was taken off-line to have the batteries changed.
It does that extremely well. That’s what it’s for. And one of the ways that it meets the challenge, which is a very big challenge, is by keeping each individual end device, including lightbulbs, pretty stupid. Very low processing power. Very little in terms of retained state. That’s why the batteries last so long in the battery powered devices. That’s why the lightbulbs can cost only a couple bucks more than their nonnetworked cousins.
It’s entirely possible to add a device to monitor energy going on and have it reset all the bulbs if you want. It can be done now. But it’s going to add cost and it’s going to require adding a device that sophisticated enough to keep track of the states.
If you want constant state monitoring with minimal custom work, go to Wi-Fi. Pay $120 for a lightbulb. Quadruple The network’s energy use over a month.
All 3 solutions are good solutions but they solve different problems.
Apple believes that residential home automation customers think with the Wi-Fi mindset. They demand constant monitoring. They’re willing to pay the extra in terms of dollars per device and energy use for the network. So Apple is using Wi-Fi and constant monitoring for HomeKit.
If you live in an area where your power goes out a lot, and you hate it that the Bulbs come on at full brightness, you have multiple choices.
One) don’t use zigbee bulbs. Use switches instead.
Two) add an energy monitoring device and a scene storing smartapp, and have it reset when power is restored
Three) use a whole house backup system
Four) while you’re away on vacation, run something that turns the bulbs off every once in a while.
All of these are possible. They have different costs. They have different pros and cons.
The manufacturer’s guide for every zigbee bulb says the bulb is intended to operate with constant current. If you’re going to use that tool, then that’s part of the operating directions.
If you need to solve a different problem, then you may need a different tool. But you’re unlikely to find one for $15 per device. So it all comes down to what your own priorities are.