I'm not sure if this is what the GP meant, but the universe doesn't need to "end", as such (it's a bit hard to word properly, as "to end" also implies some (ver

I'm not sure if this is what the GP meant, but the universe doesn't need to "end", as such (it's a bit hard to word properly, as "to end" also implies some (very final) notion of time), just the perception of time? Like if the universe is this Block Universe, being the complete state space of everything, wherein these "conscious structures" exist (that are us), which are connected by causal steps (possibly branching), these steps being tied by the rules of physics as we experience them. Perception of time exists completely within these structures. The concept of "when the last human (or animal or alien)" dies, in this context, just points to a region of this state space beyond the boundaries of these conscious structures. Doesn't mean "there" does not exist.