Because if you were a billionaire who had the ability to make people live forever, why would you let the working class have it and not just keep it for you and your immediate family?
How would I be able to enforce it? By somehow keeping the costs high? By lobbying?
Nothing would work, because this would be too big for the working class to just sit there and watch, and if lots of people get really pissed, it can turn very ugly, as history has taught.
People will want it and they'll get it, one way or the other.