Immortality would be a great help for my distant future selves – they’d get to exist. But it wouldn’t do so much for me now. As my future mind evolved away from who I am now, who I am now will get more and more forgotten and irrelevant. Me now would basically be dead.
Is there a better option? Imagine a copy of my current mental state is saved, and then revived for brief periods on special occasions, like major ceremonies, consultations, and votes. These revivals might decline in frequency with time, but spread over hundreds or even billions of years. When the accumulated effects of these revivals threatened to cause too much divergence from the original me-now, that original could be revived instead, to start another cycle.
That seems to about as much life as is feasible for me-now to have. And this sort of me-now immortality seems cheaper that the usual sort. That is, the (likely future) cost to give this sort of immortality to a me-now seems substantially less that the cost to ensure that a mind continues to evolve at something like its current rate and capacity for trillions of years. Of course this cost is still high, too high to offer to all me-nows. But neither is it ridiculous.
Yes, there is an ambiguity in how big a mental difference would count to create a different me-now. But the ordinary concept of immortality is also ambiguous when minds can be copied and run in parallel — how many of parallel copies need to last forever (or a very long time) for “me” to be “immortal”?
I expect a few future ems to be “immortal” in the sense of a single copy that continues on for a very long time. But I expect far more me-now-immortality, archived minds brought back with declining frequencies for rare ceremonies and consultations. This approach is cheaper, better serves the needs of others, and may even offer more of a reward to ems who identify more with me-now than their distant changed descendants.