Basically that would mean anyone without millions to cover the possibility that they might buy a 747 for personal use is "living above their means" - since anyone can encounter buying a 747 for personal use or several smaller business jets at the same time that their savings might not be high enough to handle, even if they were living well below their means up until the point of the emergency and catastrophic events.

Nope. Doesn't work. It only becomes LAYM when you actually buy the jet(s)... or incur the medical expense(s).

Except when you go to the 747 jet store, you know how much the product costs before deciding to buy it - with medical care, not so much.

By your definition than Living Below Your Means or Above Your Means is never something you're doing in the present - it's only by analzying the past that you can determine if you covered all your expenses at any given point in time. Sorry but that's not the definition most people use.