Because there is a non-zero chance that at some point you'll need a medical procedure that is, even at non-inflated cost price, more expensive than your net wor

Because there is a non-zero chance that at some point you'll need a medical procedure that is, even at non-inflated cost price, more expensive than your net worth in order to survive; and society considers it unethical to let you die in that case. With the same reasoning you're not actually the single payer for your food, and food stamps exist.