This. The idea that small societies behave differently than large ones seems inherently obvious to me. Then extrapolating the proposed optimal behavior of small societies (not that I think that the advocated behavior is even correct) to large is beyond bizarre.

It's not as simple as "we are fine now, so we don't need to think". These words are typical of people in first world countries who have grown comfortable with civilization. You should think about things more deeply, first. Here are some questions you might want to think about:

Do you think being prepared for a possible scarcity situation is not useful? Will the human population continue to grow indefinitely? Will humans ever run into resource saturation? Are cataclysmic environmental events actually possible? Name 3 examples. How would each of these example events effect population size and resource availability? Are there societies in our world today which are more or less social islands (hint: yes)? How would the luxuries and rights you have grown comfortable with fare in those societies?

After pondering these questions, it's hard to justify that nobody should be thinking about these issues, or that it's too early or not the right time to be thinking about these things. It is never not the right time to think. Do not let anyone convince you otherwise. You can and should think about anything and everything. I am deeply saddened to see your statement, actually. Is this what we are?