The previous commenters are correct. T1D here. Sorry for the book.
I think you are correct but you may be overstating the case when you say, "healthy people can stay active for weeks without food". Carbs, yes. But its worth noting that Zach Bitter, who holds records in ultra marathon emphasizes multi-modal fueling for lack of a better frame, i.e ketogenic leaning for fat burning and carbs when needed; not perfect ketogenic diet. As we like to say on HN, "dynamic at run-time".
Exogenous insulin is the root cause of most hypoglycemia in insulin-dependent diabetes. There are other causes but they are relatively minor. Exercise, alcohol. Most people do not exercise or drink in a focused enough way for those to be major causes of hypoglycemia in insulin populations.
Insulin is just another pill with dramatically worse side effects than an actual pill, except maybe macrodosing psychedelics instead of microdosing glucagon.
You are correct in your macro diet analysis, except that fasting and ketogenic approaches are far more complex in concert with exogenous insulin than most people realize. If you have an endocrinology or organic chemistry background, this may be worth a shot; but the biochem is complex.
The LSS of your last question is that you don't have discrete conscious control of gluconeogenesis or much else in metabolism because it is all driven by well-functioning hormonal changes in the autonomic nervous system.
Again, "dynamic at run-time". The dynamics of insulin, glucagon, exercise, and fasting are far too complex to make this a one and done, simple prescriptive approach.
It's unusual, but I've practiced these approaches for decades, much to the chagrin of my health care team. That team being highly educated and experienced know the statistical outcomes and they're not good.
There are numerous problems with these approaches in diabetic populations who may not have the genetic sensors which make these states survivable, i.e. not all humans can feel changes in glycemia so overdosing insulin is a daily challenge to survival.
CGMs are not a cure-all either since the veracity and failure rates are poor by medical device standards.
I should know. I've worn a continuous glucose monitor for more than five years including two CGMs concurrently the last few years. They work great for some people.
In my case, they're horribly inaccurate (off by hundreds of md/dl) and when I was wearing a closed loop insulin pump, they are root cause of both overdose and underdose states leading to damning hypo and hyper glycemia since the pump has no way of knowing it's being led astray. I'm sure this is covered in cybernetics, control theory 101, or the like. At least I hope so.
Some, like me, can feel the glycemic changes and this promotes survival. T1D without glycemic sense may be a death sentence because the path from consciousness to unconsciousness is quick and these states are frequently not survivable without immediate action or a world class ER trauma team.
There's a reason T1D is classified as a wicked problem, like COVID.
This is why nocturnal hypoglycemia is dangerous even for those who can feel glycemic changes. Trust me, after 50 years of playing this game nightly, I'm not kidding when I say it takes Goggins-levels of asceticism, compulsiveness, and self-care.
I believe it's worth R&D spending and a cohort like me who have the biomarkers for surviving these approaches, but n=1. There may be others but I've not interacted with them directly.
Here's a well-cited oldie but a goodie on the complexity of diabetes for the obsessively curious:
https://www.researchgate.net/profile/Philip-Cryer/publicatio...