Here is a thing to consider: as folk grow older they generally grow wealthier at the same time. There's nothing magical about this, of course. The longer you have to save and invest, the more you will have saved and invested. I'd imagine that the freedom and security that comes with not living hand to mouth or as a dependent is one of the more important reasons why older people are generally happier than younger people.
Older people also have the greatest need for the fruits of longevity science: better ways to treat age-related disease, but more importantly ways to reverse the course of aging by repairing its root causes, the various forms of low-level biochemical damage that accumulate over the years. So you might think that there is a fortunate confluence of circumstances here, in the the people who most need rejuvenation biotechnologies are also the people who have more in the way of resources that might help fund its development.
But there are perverse incentives at work here. The older you are, the less time you have to wait for the results of research and development to arrive. If you don't have decades to wait, then you are unlikely to benefit personally - unless you can write a check for a few hundred million dollars to the SENS Research Foundation and later buy yourself a couple of labs and clinics in less regulated Asia-Pacific countries to move directly to clinical application without going through the FDA or other equally hostile regulatory bodies. But most people can't do that, and there are few bold billionaires in this sense; most embody their own businesses and look little beyond them. The Elon Musk or Richard Branson of applied longevity science has yet to emerge.
So for the rest of the elder population, and from the raw self-interest point of view, there is no incentive to give meaningful sums to longevity science when the first rejuvenation therapies are, under the very best scenarios, at least twenty years away. Few people even see that possibility, offered by SENS if large-scale funding arrives soon, as most researchers in the longevity science mainstream tell the world that results are both far further out in time and will not achieve actual rejuvenation when they do arrive. So the old have diminished incentives to do anything to meaningful advance the state of research even as their bodies are constantly reminding them of their ongoing degeneration.
The young, of course, are extremely talented at ignoring the future. Humans, I should say, are extremely talented at ignoring the future - but the young don't yet have the constant nagging pain and lost-function reminders of a failing body, they are usually not on first name terms with the local medical community, and nor do they have as much in the way of money to donate to research into applied longevity science.
So the incentives founder at both ends of the human life span. You need vision if you're likely to benefit personally and selflessness if you are not, and neither of those things are as common as we'd all like them to be.