No one seems to want to face the fact that most human beings do not deserve to become immortal.
The problem is choice. Most human beings choose to be pigs. They know how to behave well, but they choose to act like jerks, instead.
If every signal human being on Earth today suddenly became immortal by, let's say, some kind of airborne immortalizing nanobots, what do you think would be the results for the future of humanity?
If I were given a 5,000 year lifespan, and a kind of Krell brain boost, the first thing I would do would be either to leave the Earth, or to find a big castle far from the maddening crowd.
Civility
Here is a poll for you:
The Nobility of present day humans