My personal opinion is that problems like these will be solved in a very mundane and brutal way. Future people will be much closer to "fitness maximizer" concept than homo sapiens is, and ideas like humanism will be abandoned. Physical immortality does not mean living forever if leading causes of death are war, murder and capital punishment.
Death, long lives, uploading
Mark Rosenfelder (aka zompist, of language construction kit fame) writes about the advantages and drawbacks of mortality and its alternatives, in fiction and real life. Rosenfelder, as an author, clearly takes Fun Theory very seriously. After discussing the mental and physical decline that age usually entail, he assumes that the most difficult to surmount of these problems will be the loss of mental flexibility and tolerance of novelty. He then uses this obstacle to offer interesting fun-theoretic arguments against uploading and cryonics:
And how he addressed the issue in his own far-future conworld: