It seems to me like I'm arguing the instantaneous rate of death will be lower afterwards, since there's a swath of elderly people missing from the population, b

It seems to me like I'm arguing the instantaneous rate of death will be lower afterwards, since there's a swath of elderly people missing from the population, but you're arguing about the average reverting over time (and specifically that it won't revert from the impact of the pandemic). I don't think the premature death impact of covid will be that large compared to, say, obesity or diabetes. So the impact on the average won't be severe & could be easily offset if our public health leaders produced actual positive results. Instead we've got an unhealthy population and no one accepts the blame.