It is clearly impossible to foresee all future catalyst events that will significantly impact human lifespan. The situation is thus imperfect. Yet this serves to illustrate the even greater imperfection of ignoring future catalyst events that are now known.
The environment and conditions that fostered previous improvements is by definition unique as the resulting improvements bring about ever changing scenarios.
In particular, the recent past 40 or so years represent a very unusual period of UK mortality experience when viewed against a wider backdrop spanning very long periods. This in itself adds to a viewpoint that warns against the sole use of projections largely based on this period.
Furthermore, basing future mortality improvements upon recently observed changes in death rates can significantly delay recognition of mortality improvements.
This implicitly imposes the requirement that widely acknowledged drivers of increased survivorship first need to have their effects clearly signposted in death rates before they can be accounted for.
This lethargy in response is demonstrated here.