"Any non-internet connected clock (microwaves, cars, toys, $10 alarm clocks, wristwatches, etc) will not be able to respond to these types of changes."My post about 19th C. timezones and train timetables is about this very point. All these independent systems are independent 'timezones' and that's the problem - and it's a fundamental one!
First, closed systems are intrinsically subject to drift and will never really be on time anyway. Second, there's nothing wrong with an independent closed system having a 'clock' - 'oscillator' would be a better word here - but it was all too convenient to couple this with external time systems. In essence, independent closed systems will never be in sync with external time.
If closed systems have to have time clocks that are an analog of real-world time then they should always be considered an approximation as with all analog systems. Relying on them for accuracy has to be a last ditch resort.
The trouble is that we never adopted this newer mindset from the outset of digital systems, instead we simply repeated the earlier mistake of every town having its own timezone.
There are ways around these problems just as there were in the 19th C. but no one has bothered to implement them.
This is not the place to delve into them except to say that they involve both technological solutions and an automatic assumption by humans that closed systems cannot be relied upon to provide accurate time.