As I've pointed out in the past, the concept of "successful aging" looks more and more awkward and ill-thought the closer you examine it. At the high level the idea is connected to compression of morbidity, pushing disability and frailty further out into old age without extending life - but are these things even possible as goals for medical science?
It seems likely not: either you extend life or you don't; either you treat aging by slowing its progression or reversing it or you don't. Aging itself is by definition a degenerative medical condition that causes pain, suffering, and death - so the idea of aging successfully seems a contradiction in terms at best, and at worst a sort of propaganda intended to deliberately cloud the issue of what should be done by the medical research community:
Increasing longevity is one of the great achievements of our civilization, but it has also given rise to discussion about good and successful aging. The concept of successful aging has attracted much debate, but there is still no universally accepted definition or standard measurement tool for it. The Encyclopedia of Aging defines successful aging as survival (longevity), health (lack of disabilities), and life satisfaction (happiness). It appears that the main sources of difficulty lay in the ambiguity of the meaning of "success," in the complexity of the aging process, the rapid changes taking place in society, and the changing characteristics of the older population.
Discussions on successful aging have taken two main perspectives: one defines successful aging as a state of being, while the other understands it as a process of adaptation, described as doing the best with what one has. Studies taking the adaptation approach have often found that older people themselves feel they are aging successfully, even though traditional quantitative models say otherwise. Successful aging as a state of being, then, is an objective measurable condition at a certain point in time, demonstrating the positive extreme of normal aging. The most influential model of successful aging as a state of being was introduced by Rowe and Kahn, who characterize "success" as absence of disease and disability, maintained physical and mental functioning, and active engagement with life. Many studies and definitions take the view that successful aging is possible only among individuals without disease and impairment.
Obviously such categorizations are likely to exclude most older people, typically the oldest-old, from the possibility of successful aging.