I think you may be treating your continuation as a binary affair (you either exist or don't exist, you either experience or don't experience) as if "you" (your mind) were an ontologically simple entity.
Let's say that in the vast majority of universes you "die" from an external perspective. This means that from an internal perspective, in the vast majority of universe you'll experience the degradation of your mental circuitry -- whether said degradation lasts ten years or one millisecond, you will experience said degradation up to the point you will no longer be able to experience anything.
So let's say that at some point your mind is at a state where you're still sensing experiences, but don't form new memories, nor hold any old memories; and because you don't even have much of a short-term memory, your thinking doesn't get more complicated than "Fuzzy warmth. Nice" or perhaps "Pain. Hurts!".
At this point, this experience is all you effectively are -- it's not as if this circuitry will be metaphysically connected to a single specific set of memories, or a single specific personality.
Perhaps at this point you can argue, that you totally expect this mental pattern to be reattached to some set of memories or some personality outside the Matrix. And therefore it will experience an afterlife -- in a sense. But not necessarilly an afterlife with memories or personality that have anything to do with your present memories or personality, right?
Quantum Immortality doesn't exist. At best one can hope for Quantum Reincarnation -- and even that requires certain unverified assumptions...
Perhaps at this point you can argue, that you totally expect this mental pattern to be reattached to some set of memories or some personality outside the Matrix.
There should be some universes in which the simulators will perform a controlled procedure specifically designed for saving me. This includes going to all the trouble of reattaching what's left of me to all my best parts and memories retrieved from an adequate backup.
Of course, it is possible that the simulators will attach some completely arbitrary memories to my poor degraded personality. This...
If you don't believe in an afterlife, then it seems you currently have two choices: cryonics or permanent death. Now, I don't believe that cryonics is pseudoscience, but it's still pretty poor odds (Robin Hanson uses an estimate of 5% here). Unfortunately, the alternative offers a chance of zero. I see five main concerns with current cryonic technology:
So I wonder if we can do better.
I recall reading of juvenile forms of amphibians in desert environments that could survive for decades of drought in a dormant form, reviving when water returned. One specimen had sat on a shelf in a research office for over a century (in Arizona, if I recall correctly) and was successfully revived. Note: no particular efforts were made to maintain this specimen: the dry local climate was sufficient. It was suggested at the time that this could make an alternative method of preserving organs. Now the advantages of this approach (which I refer to flippantly as "dryonics") is:
There is one big disadvantage of this approach, of course: no one knows how to do it (it's not entirely clear how the juvenile amphibians do it) or even if it would be possible in larger, more complex organisms. And, so far as I know, no one is working on it. But it would seem to offer a much better prospect than our current options, so I would suggest it worth investigating.
I am not a biologist, and I'm not sure where one would start developing such a technology. I frankly admit that I am sharing this in the hope that someone who does have an idea will run with it. If anyone knows of any work on these lines, or has an idea how to proceed, please send a comment or email. Or even if you have another alternative. Because right now, I don't consider our prospects good.
[Note: I am going on memory in this post; I really wish I could provide references, but there does not seem much activity along these lines that I can find. I'm not even sure what to call it: mummification? Probably too scary. Dehydration? Anyway feel free to add suggestions or link references.]