You're assuming some sort of pattern theory of identity when you consider uploads a potential form of survival. If you go all-out pattern theory of identity and assume we're in a big world, is there a reason why the subjectively subsequent moments of awareness need to actually take place at increasing time points on the universe's timeline? A state of matter that corresponds to your pattern's subjective t + 1 might have occurred at the universe's t - 10000 at some distant light cone. If your mind stays at any finite size, it'll eventually just end up going over the same states again, so you could just get an unbound subjective experience timeline inside a fixed timeslice of a spatially infinite, temporally finite universe.