This seems a bizarre claim. If there is an end to time then even in flat space-time, if the region we can access starts out finite and grows at a finite rate, then when time ends it will have a finite maximum volume.
Which, according to the Einstein Field Equation, there can only be if the universe is closed, i.e., finite in size. I wasn't talking about what's conceivable logically; I was talking about what's actually possible, physically, given our best current theories.
In any event, "resources we can access before time T" unequivocally finite, and some needs must be met before time T for any T far enough out that it dramatically changes the resources we have available. Which means that in terms of considering distribution and making sure needs are met, there is a theoretical upper bound on the resources available, and zero-sum thinking would be appropriate once we have allocated enough to some individuals that there is literally not enough for others and have reached limits on improvements in efficiency. As I've said, I'm not at all convinced that we are near either.
> Actually, if the universe is spatially infinite (which it is according to our best current models), this is not true
If the universe is temporally finite, it is, even if the universe is spatially infinite.