To suffer or become incapacitated is to diminish the utility of being alive. The way to minimize this loss is to work towards removing the causes of suffering and incapacitation. The greatest such causes are medical, and of those, aging is by far the largest. Similarly, to die is to suffer the loss of all that one might have been and done after that time. It is a tragedy that any individual ceases to exist. The way to minimize this loss is to work to remove the causes of death. The greatest such causes are medical, and of those, aging is by far the largest. Ethically, the case for working to extend healthy human life spans by treating aging as a medical condition is very straightforward. Objections are trivial in the face of more than one hundred thousand deaths every day, tens of millions every year, and the ongoing suffering of hundreds of millions more.
Will life-extension treatments be prohibitively expensive? The diabetes drug metformin is a classic candidate for a possible anti-aging pill. And the cost of this possible wonder drug? Retail costs for 60 tablets of 500mg of metformin (a 1-2 month supply) range from $9 to $16, even without insurance. Other potential life-extension molecules are similarly cheap. Glucosamine costs as little as ten cents a pill, has been the subject of several recent studies showing it decreases all-cause mortality by as much as 39%, and may be as effective for longevity as exercise.
What about newer anti-aging medicines? Is there evidence that newly discovered and developed drugs would be similarly inexpensive? It's likely. Take vaccines. Vaccines are a good parallel to anti-aging medicines because they are developed to treat a deadly, widespread disease that impacts large swaths of the human population and they thus have a huge demand and a requirement to distribute to the most people possible. Developing a vaccine can cost as much as $2.8-$3.7 billion and yet many vaccines, including those for the most widespread diseases, are offered free-of-cost or at very low prices. For example, the flu vaccine is often free and almost always fully-covered by insurance. Other vaccines can be had, even without insurance, for as low as $6.
If, despite the above, life-extension treatments are expensive, if they are gene therapies for example, will they remain so? In the last 17 years, the cost to have your whole genome sequenced has gone from roughly $1 billion in 2003, to as low as $299 today. And most technological innovation follows this same pattern. First an experimental, expensive innovation is developed. Wealthy early-adopters buy it (think investment bankers and car phones back in the 80s), and their purchases fund the research and development needed to improve the innovation, better distribute it, and make it less expensive. Soon, every person who wants one can afford it, and at a much higher level of quality than the original that was available only to the rich.
High initial prices of a new product are thus almost an extended form of R&D funding (and clinical testing with data provided by early adopters). The rich are essentially paying the money necessary to further develop the product and get it to the masses. What the rich pay for with money, the poor pay for with time. It's the reason the smartphone in your pocket only costs a couple hundred dollars, and you don't need to lug a car around to use it. It's also the reason your Apple Watch isn't the size of a room, and yet can do way more health monitoring than the early electrocardiogram machines could (and at a significantly lower price).
Intuitively, anti-aging medicine should even help lower the total cost of medical care for people, as individuals will have to spend less on treating the very expensive chronic diseases of old-age like Alzheimer's or cancer. These health-cost savings from longevity medicine are often referred to as the "Longevity Dividend." Contrary to popular belief, the real money in almost any market is not in selling boutique treatments to a few billionaires, but selling commercialized interventions to the millions (and, globally, billions) in the middle and lower classes.