No space, biology, chemistry and time aren’t good enough reasons to justify forcing others to keep you alive. You’ve no objective reason to force others to pay for your healthcare beyond “society” and “everyone else is doing it”, you’re just appealing to bandwagon and authority.

Objectively speaking, healthcare is a universal need as it’s something every living person needs. Logically, since we know everyone needs it, and we understand morally that barriers such as the ability to pay for help shouldn’t block someone from receiving help, the only reasonable thing to do is off-load the cost away from the individual. Otherwise, you have immediately built a system where only certain classes of people (those who can afford it) get good quality of care, and the rest go without.

To your point about how nothing is a good enough reason for you to keep someone else alive, this is a horrible worldview that has led to the near-collapse of our society. A better approach here would be for us to agree intellectually that there’s no good enough reason TO LET SOMEONE DIE and to charge the government with building institutions towards that goal. It turns out that through taxes, we can abstract away from individual healthcare costs and frame a system where every single person in need can be covered. For a government charged with securing life, liberty and the pursuit of happiness, I’m not sure I even see another way forward.