PomBear - I'm really that sad, too
and love extended monologues talking about books, especially with exceedingly rare MNers like you who don't take personal offence at their favourite books being criticised. Thank you for letting me 
"They do go fishing, but they debate the date because to actually admit there isn't going to be another season etc means admitting that it's the end of everything, and it's hard to do."
I understand that admitting one's own doom is hard to do, but you would expect at least most of the rational adults to have come to admitting it a long time ago and started doing something about it. As I said before, start making super-thick animal skin clothes and plan to move further south to Antarctica on that submarine of theirs, for example. Why the hell don't they do this? Normal humans would at least try to add at least several months to their lives, and who knows what will happen once they are there? Maybe something about the south pole (extreme cold? magnetic field?) will keep harm away - why not try?
Instead, they stick their heads in the sand and debate marriages, children that will never happen and fish seasons
All of them. How is that even possible in a largish group of people that there isn't even one who wants to try something (anything) against the annihilation of the human race? 
"It's like visiting someone who is very old, or ill, and they say "oh I'm not long for this world" and you say "Don't be daft, you've got years in you yet""
Yet the old man says "I'm not long for this world", meaning that he knows what is ahead. Unlike this bunch of muppets.
A comparable example would be a group of very old & very ill people talking about whether they should exercise more to look good for the ladies. You would go
and think they have gone senile, the poor dears.