There are different definitions of "we" there. Do you think of "we" as the human race or "we" as in yourself and your partner or maybe your immediate family? Not everyone thinks of "we" in the same way.
If you're so narcissistic/nihilistic/whatever as to fall into the latter group, what do you care? Appeals to future generations won't work on people who only care about themselves.
They also won't work on people who only care about next quarter's earnings, either, and that's another issue.
I am actually one of those nihilists, in that I have no stake in the next generation and only a faint interest in "the good of humanity", but what I care about is the fact that climate change denialism is part of a constellation of anti-intellectualism that makes my life worse today, right now.
Climate change denialism has enormous overlap with the people who promote COVID denialism. Even before that crisis, they were responsible for creationism and anti-same-sex-marriage (which has since become legal without the world collapsing).
These aren't matters of opinion, values, or world-view. They're Just Plain Wrong. Nor am I talking about fringe opinions; these are political party platforms and talking points that candidates rely on to attract voters.
There are tons of other areas where I am quite certain they're wrong, but more importantly, they argue about them using the same poor forms that they use for climate change. They cherry-pick, they are manipulated by deliberate disinformation, and they place their own ignorance over knowledge.
That creates a hostile, toxic atmosphere in which there is no way for me to convince them, even on the things that are as conclusively scientific as it's possible for a thing to be. That makes it beyond impossible in areas where there might actually be room for legitimate disagreement.
So yeah, I care a lot about climate change, but not because I'll be alive, nor my direct descendants. The way we talk about climate change makes my life a lot worse, today. I believe that we've seen a deliberate inculcation of an anti-intellectual bent in the US that has become weaponized.
Maybe I'm not rich enough to get it, but let's say I do only care about me, and no one else. In the event of catastrophic climate collapse, sure, I could hypothetically escape on my evil villian billionaire yacht to Oceania, but even if I'm personally fine, my estate (as rich people call their houses) is going to be destroyed. My Miami beachfront condo is literally underwater, as is my Venice summer home, and NYC condo.
Let's say I'm rich and selfish and care only about things and not people. If I bother to look into the future, don't I have more real estate to lose than the poors, who might have one (or fewer!) homes to lose?
Your second point, that long term thinking is hard seems to be a bigger issue, even more so for anybody who is living paycheck-to-paycheck. It's too difficult to get rid of, eg, single use plastic in my life as an ordinary consumer. How do we set things up so the system is incentivized to change itself? Especially when the culture is opposed to any change in the first place.
I didn't really bring up rich vs not rich, because it's more about empathetic vs narcissistic or societal vs anti-social. The event of a catastrophic climate collapse that you describe is probably not going to happen in our lifetimes, so if you're of the anti-social mindset, what do you care what happens to the Earth or society at large, especially after you're gone? Some people aren't going to change their behavior for the benefit of people they'll never even meet (separated by space or time), let alone never care about.
If you're so narcissistic/nihilistic/whatever as to fall into the latter group, what do you care? Appeals to future generations won't work on people who only care about themselves.
They also won't work on people who only care about next quarter's earnings, either, and that's another issue.