Are you serious?
A life is a life, no matter how old or how young, and unless you are going to break down and tell me the insurance companies/government bodies are filled full of oracle's; there is no way of knowing how much or how little each persons life is worth or how much longer it will last. Most people, including myself, have either paid for or had insurance paid for them since a very young age. Why? So we/they don't have to pay out a huge bill if and or when something happens. That was the whole reason behind insurance programs when they started. To say that because someone is old and may not have that many payments remaining is ridiculous, most likely the elderly person has already paid in more money than most of the teenagers will before they raise up and strike against having to pay for it all.
Just put yourself in those shoes and I think your opninion will change. Imagine being 70 years old, needing hip surgery, but otherwise beeing in great health and getting rejected because of your age - what do you do now?
This very thing happened to my grandmother (only she's 85), except, they didn't reject her and now she's fully recovered and living her life just as she was before. Her primary daily job? Helping others that are less fortunate.