Thanks to a great deal of hard work and advocacy, there is now a much greater enthusiasm and public discussion in the research community regarding treatment of the causes of aging than was the case at the turn of the century. This is as opposed to continuing the past strategy of attempts to patch over the late stages of age-related diseases without addressing their root causes. Nonetheless, many researchers are still reluctant to openly advocate for significant extension of human life spans, and bury that goal in favor of talking about compression of morbidity, shortening the period of disability at the end of life.
What is the point of the exercise, however, if not to aim high, at pushing out the duration of both health and overall life span by decades and more in the only practical way possible, which is by repairing the damage that causes aging? We are machines, and like all machines, our working, fully functional life span is determined by the degree of ongoing repair. Only when repair fails will we decline. To my eyes, failure to acknowledge radical life extension as a primary goal only serves to strengthen support for poor approaches to the treatment of aging, strategies such as calorie restriction mimetic drug development that cannot possibly produce meaningful gains in healthy human life spans - because they not not forms of repair, only ways to modestly slow damage accumulation.
Life extensionism is a global movement with long-term traditions. The idea, that aging is similar to a disease and should be treated as such, was first suggested in the early 1900s. Since then, the study of aging biology has revealed the underlying processes of aging, such as DNA damage, toxic proteins aggregation and cross-links, cellular senescence, nutrient sensing deregulation and others, and proven the plausibility to address these processes to modify the dynamics of aging.
Even though aging itself is not described as a disease in the International Classification of Diseases (ICD), there is no doubt that aging is the major cause of many severe diseases, and the global population could benefit from bringing aging under medical control. Many existing drugs have been found to be geroprotective (protecting the body against the the aging process). However, what would happen if scientists applied geroprotective technologies to humans, remains a subject of numerous misconceptions.
This is the human life course as it was before the development of modern medicine: somewhere around their 50s people started to develop different age-related diseases, then died from them some 15-20 years later. As a result of the past century of development, however, now people reach their 50s, age-related diseases start to manifest, but modern medicine allows us to slow down their progression, so people live longer - but this is the period of illness that is extended, because this medicine fails to address the causes of aging. This is exactly why Brian Kennedy from the Buck Institute calls our healthcare system a "sickcare" system: we are keeping people alive for longer, but we are keeping them sick, generating a burden for our system of healthcare and social support: we have many people living longer in disability.
We can do better by developing interventions to address the aging processes. These interventions are meant to be applied in middle age, before the manifestation of age-related diseases, in order to extend the healthy period of life, or healthspan, while the period of illness is postponed and will remain relatively short. This could allow people in their 50s to look like they are 30, and in their 70s also look younger, be stronger, and feel as good as in their 50s. So what we mean by life extension is actually the extension of the healthy and productive period of life, free of disease and disability. In this "extended" society the majority of people could enjoy their lives for much longer and actively contribute to the development of the economy regardless of their chronological age.