I agree with you.
The 80% you'd toss out is worth a lot of money too and that money may be better spent on something that stops the boat sinking in the first place... Like better weather services for offshore passages etc.
How many times have you been told: "you can't afford not to have this! Your life may depend on it"?
I get told that all the damn time by everyone for everything, even the doctor the other day wanted to book me up for a lot of tests that do nothing, show nothing but are EXPENSIVE. And look askance at you when you tell them to shove it!
Seems like you are saying here that an ounce of prevention is better than a pound of cure. I would agree with that. And yet you're applying the philosophy to catastrophe on your boat but not for preventing catastrophe in your body???
Beware those that tell you what you MUST have.
Yes, you should be ware of those that tell you you must have something IF they are a salesman. Your doctor is uniquely positioned to be impartial as your
advocate. Second opinions are often a good idea for peace of mind but I'd advise you to trust your doctor a little more.
How is this related to the thread you may ask? Well the most often glossed-over part of the ditch bag is the medical part even though a high percentage of life raft occupants are injured. I think it's just too intimidating for most people.
Using Mark's philosophy on prevention (which I AGREE with), all the (expensive) kit in the world may not be as good as being healthy to begin with. To that end, I'd say that if you enter the raft and have a heart attack from the cold water shock you may wish you'd had those tests your doctor wanted for you. If you die of kidney failure while trying to ration your water, you might wish you'd had those tests as well....
Preventive maintenance for boats, and preventive medicine for people. Both are critical for this type of survival.