Amazing! You've figured out insurance!
And if this is the case (which I don't actually know for sure, I'm just speculating), then insurance companies would be incentivized to 'nudge' certain people towards this decision, which is a super duper slippery slope, and at the extreme end you'd have the Rick and Morty dead people spaghetti planet situation.
edit - this of course applies only to people that would have the procedures and medicine that would keep them alive covered.
Therefore, the longer one lives, the benefit accrues to the insurance co, because the more premium policy holder pays to LifeInsuranceCo (LIC), LIC has more time to earn interest/investment profits from those premiums, and the cheaper the payout from LIC to policy holder beneficiary, because of inflation and since most payout amounts (eg $1M) are fixed at time of policy issuance.
This would make sense if life insurance and health insurance were covered by the same insurer, but they rarely are.
The more fundamental problem here is that insurance is a) to prevent financial hardship b) in the case of a rare event. Neither death nor serious illness are rare events for the elderly, and more often than not, health insurance fails to prevent financial hardship, so both of these fail as insurance in these situations.