And you're going onto a tangent that I am very much in agreement with (that the whole system is massively broken and suffers all sorts of perverse incentives), but -my- point, if you'll recall, is that not everything gets written off. People still get unexpected medical bills -all the time-, for things their insurance didn't fully cover; this despite their deductible and/or max out of pocket.
Or, as I commented before, and which you're...agreeing to, in a whole lot of words, it's a provider choice, and not guaranteed. I.e., every time you go to the doc you're rolling the die; doubly so for emergency stuff that you can't get pre-authorized. "It doesn't happen -that- often" seems to maybe be your argument, but it happens enough, and the consequences of it happening at all are devastating.