So I didn’t answer this at first because it seemed like a distraction from the main point, but since gjm brought it up:
I have a suspicion that the point of “long term investment” is that it gives you a lot of maney, and, supposedly, you are a special genius, who knows how to spend the money to help the world, better than anyone else.
You don’t need to believe that you are a special genius to believe that you would be able to spend the money better than an average person would spend it. The question of how best to spend money to help people is one that an entire community of people (i.e. effective altruists) is dedicated to answering, so the epistemically humble thing to do is probably just to believe that they are right about it. Most people aren’t trying to spend money with the purpose of helping people, so it is not very surprising that you can do better if you try.
So I didn’t answer this at first because it seemed like a distraction from the main point, but since gjm brought it up:
You don’t need to believe that you are a special genius to believe that you would be able to spend the money better than an average person would spend it. The question of how best to spend money to help people is one that an entire community of people (i.e. effective altruists) is dedicated to answering, so the epistemically humble thing to do is probably just to believe that they are right about it. Most people aren’t trying to spend money with the purpose of helping people, so it is not very surprising that you can do better if you try.