a big motivator for me used to be some kind of fear of death. But then I thought about philosophy of personal identity until I shifted to the view that there’s probably no persisting identity over time anyway and in some sense I probably die and get reborn all the time in any case.
I’m clearly doing things that will make me better off in the future. I just feel less continuity to the version of me who might be alive fifty years from now, so the thought of him dying of old age doesn’t create a similar sense of visceral fear. (Even if I would still prefer him to live hundreds of years, if that was doable in non-dystopian conditions.)
This is not quite deathism but perhaps a transition in the direction of “my own death is kinda not as bad”:
and in a comment: