It has been clear to me since 1974 that indefinite life extension (elimination of the detrimental effects of aging) is a technical possibility.
This is not the same thing as immortality.
Eliminating the dangerous effects of aging is only one small part of the many things that kill people.
One cannot eliminate risk completely – to live is to risk dying, and it does seem possible to substantially reduce most of the risks we face today – so that the average life span is something close to 5,000 years, with some few individuals living hundreds of thousands of years. I quite like the idea of living long enough to see the changes from plate tectonics.
If you really want to live a very long time you need to look at all of the sources of risk to life – to look very carefully at the incentive structures in our systems that tend to produce risk. In this sense, the use of markets as an allocation mechanism when we have the technical ability to produce abundance for all through automation seems to me to be the major risk (and to be clear I am not advocating equality of distribution, and I am advocating that all people have as a minimum all of the essentials of life – air, food, water, education, communication, travel, health care).
And it seems to me that we have a reasonable chance of creating systems that deliver such abundance to every person on the planet, and to achieve that sort of security, and it seems very likely that it will necessitate some conceptual changes in how we organise our social and political processes. A move to global cooperation, with massive technical redundancy, and widely distributed trust networks seems to be the sort of model that offers the lowest risk profiles in the long term.