If a life insurance policyholder dies before age 100, the insurance company loses the net amount at risk for that person's policy. (investopedia.com)
You have a higher risk of dying because you are older, but they also have a lower amount at risk, so the two should even out. (insuranceandestates.com)
... and it's why the net amount at risk decreases over time (though sometimes not in a strictly linear fashion). (monegenix.com)