I know you are very new to SmartThings, and different people use the same terms in different ways. My apologies if I was confusing. 
In the SmartThings context, “platform instability” specifically excludes local mesh issues. It has to do with the changes that the folks sitting off in the smartthings offices make, usually without telling us anything, which introduce glitches. Or “changes in behavior.“
This is the source of many of the “it’s worked fine for months, I haven’t changed anything, but this morning it isn’t working“ reports that you will regularly see in the forum.
The listed solution got my interest. Reset the breaker? Could it possibly be an issue related to dirty power / inductive RF interference caused by faulty wiring in the home?
In some cases perhaps, but there is a long-standing known issue with GE zwave wall switches which has nothing to do with the wiring in the home. And which is solved by a circuit breaker reset. So my guess is that’s the one that support has in their solutions database.
Again, it’s been discussed in the forums many times, but what happens is that the GE zwave switches (not the zigbee switches) Sometimes manage to get themselves into a kind of buffer overrun situation where they stop processing network commands. You can’t fix it from the network and you can’t fix it just with the airgap switch. But if you cut the power to the circuit entirely and then turn it back on it essentially does a reboot of the internal zwave processor and often fixes the problem. This isn’t a smartthings issue or a zwave issue: it’s specific to the GE Zwave model switches.
GE ZWave Switch connectivity issues
on a schedule…
I may be mistaken, but I was not on under the impression that it was happening on a regular time schedule. Just that it was intermittent with one device for a while, and that device was OK and it was intermittent with a different device.
{ which model hub}
Yes, that would be good to know.
There are so many variables, and those variables can have different impacts.
True, but I’ve been a network engineer for a long time including in the field, and I’ve been a smartthings user for about five years now, and there are some problems which occur on this system with much more frequency than others.
No question, to troubleshoot anything further, we would need brand and model number of the devices and more details about the specific individual problems before we start trying to diagnose from a distance. 
p.s. you are right, of course, that in terms of broadcast licenses Wi-Fi is a low power protocol. But in terms of Home Automation specifically, it is considered a high power, high bandwidth option.