I suspect that much of what passes for immaturity (among adults) and egotism is, in no small part, the inability to see very far down the road. If you don’t expect to live a long while or can’t even conceive of a life in some future decade, then instant gratification makes a great deal of sense. Ditto for near-term and long-term dangers. It’s probably something we inherited from our hominid/savannah-trained brains many thousands of years ago. Stated differently, it’s hard to hold complex thoughts clearly and modern science gives us lots of these to wrestle with. It can be painful and, so, desirable to avoid. This would explain some of the anti-vax sentiment and climate disaster denial.
Whether there are parallels between personal experience and broader social sensibilities is an interesting issue. I have a long-term interest in the question of whether increased human longevity has begun to affect how we, at the societal or at the species level, see the world: whether our perspective and values change as a result of having a longer runway ahead of us.
Part of this has to do with understanding the age of the Earth and cosmos. It was not until the 19C that science (first geology, then Darwinian evolution) provided a framework in which anything existed outside the biblical or other mythical (e.g. Mayan or Hindu) model. Archbishop Ussher’s famous mid-17C calculation that the world began on October 22, 4004 BC was widely influential in early modern Christian Europe and paired with an undetermined end date of the second coming of Jesus as the bookends of human life on earth. We now have “scientific” understanding that the universe is +/- 13.7 billion years old with some considerable number of billions of years lying ahead.
Another part has to do with human longevity or life expectancy. For the thousands of years of human development until the beginning of the 20C, life expectancy at birth was not more than 40 years. Current global averages are in the range of 72-74 years (with lots of regional and socio-economic variation). Even adjusting for the high rate of infant/child mortality, we're generally living a lot longer now; and we know it.
Finally, the nature of time has changed, too. By this I don’t just mean that we have atomic clocks. There is something different about projecting a life in which little changes or changes in repeated cycles (as was the case for most of the world until the modernity of the 18-19C) as compared with projecting a life marked not only by the normal rites of passage, but also news, technology, and other aspects of visible change. It’s been normal for many people to look at their children (and, increasingly, grandchildren) and see different and often improved standards of living (aka “progress”).
The extension of human longevity looks likely to continue, not only through the continued improvement in public health which has drastically reduced infant/child mortality, but through the inundation of new medical treatments and other aspects of human health. I would bet that the number of people in their 90s that you know is far higher than for your parents or grandparents. Population projections look to a major increase in “older” folks over the rest of the century.
So, the question is whether these broad social changes have led to a different outlook on the world; what we might call “modernity.”. In this regard, there is an interesting parallel to the idea of climate. Now, people have been talking about the weather for many millennia (though not actually doing anything about it). Various ancient Greek and Chinese scholars talked about climate, but usually as a function of planetary influences or basic geography. But awareness of more fundamental shifts in the climate, including temperature and precipitation looks like it dates to the Enlightenment, with a burgeoning of studies in the 19C where climatology as a more-or-less formal branch of science emerged.
In other words, a change in mentality--an awareness of climate change—had to precede the consideration of how climate was changing and what the implications might be. The same is broadly true of demographics; with Thomas Malthus (~1798) as the landmark of that branch of study. Similarly, an awareness of longevity changes has to precede a consideration of how those changes are altering our awareness of living longer and our resulting time horizons.
In the context of climate, it is only in the past fifty years that humans have moved from awareness to reflection to action. In the context of longevity and time horizons we are only beginning to digest the actual changes in human lifespans and figure out what that might mean.
The implications run far beyond the questions of the solvency of pension plans and Social Security or changes in the composition of the labor force. Will greater familiarity with one’s great-grandchildren (a pretty rare phenomenon well into the 20C) encourage longer term thinking about families and the worlds in which they will live (based on historical projections, a child born today will have a pretty good shot at living into the 22C)?
It is certainly arguable, on the other hand, that egocentric human nature (“It’s all about me.”) won’t be much altered by the prospect of future generations (historically, there’s not much evidence of that so far). Still, the prospect of present generations living longer might be more effective. A 35-year-old (born in 1987), aware that they have a good shot at another 50 years might give greater weight to infrastructure (i.e., long-term investment), climate change, and even retirement planning than a 35-year-old born in 1787 who had only a 20-30 year horizon.
One of the few useful “lessons of history” is that social change usually takes a long time and epistemological change takes even longer. The notable extension of human lifespans has only been happening for a hundred years and is still very much in progress. Our adaptation to this new shape of humanity is also evolving. Future historians will get to look for the signs of change in our lives and attitudes.