Assume that many-worlds interpretation is correct and quantum immortality is true. Essentially, in at least one universe you survive no matter what dangerous things you try. Since there is no defined biological "expiry date" on your body, you end up in state where your body just continues avoiding terminal shutdown. Your body is failing but the space of probabilistic events (such as a given organ failing, or a given blood vessel rupturing, or two given molecules interacting, or others, however minor) which lead to terminal shutdown is sufficiently large to last you for a while, with at least one universe where you still happen to be alive.

The above process probably takes a while(?). Until the entire space of events is explored (your body is finite) and you die in all universes. But in this case we don't have quantum immortality, only "maximally delayed mortality" (MDM).

We can only observe quantum immortality with relation to ourself. Thus, in the universe where you survive, everyone else around you is likely to be dead, since the probability of two individuals surviving to this stage in the same universe is much smaller than the probability of you alone surviving. Therefore, you end up in an incapacitated state of continuous (eventually, lethal) failing of your body, completely alone in a universe where everyone else is dead.

The argument in the previous paragraph does not account for new people being born. So assuming no catastrophic event killing everyone else but you occurred, there may be other people in the universe where you are. But then you will not be in a state to appreciate that towards the end of your MDM.

So, if many-worlds is true, are we all going to end up experiencing a slow gradual fade-out of life just as we experienced a gradual fade-in?