The role of biological and evolutionary factors in human behaviour in general is well established enough that it's a glaring omission to ignore it's possible role in questions of human behaviour. That's why it's ok to criticise a case like this on principal.

It's like ignoring the possibility economic factors in trying to explain some feature of society.

It should not be necessary to propose specific possible factors to make such a criticism.

Since so many people seem to want a possible account, there might be an evolutionary advantage to gaining friends leading up to and during prime reproductive years, advantages that are lesser as you transition past those ages.

Just like our brains are more receptive to learning languages when we're younger our younger brains may be more receptive to developing friendships. Note that I've said right from the start that such details could be factors in an explanation, not that they would be the whole explanation.

ok but what could possibly have changed in human evolution in the past ~40 years (it doesnt appear to have been a problem forever)

Why do you think it's only in the last 40 years that people have found it more difficult to make friends after 30 or so? It seems like it's been like that for a long time.

Also, I've repeatedly said that biological and evolutionary details may be factors not the whole explanation, so other factors can have changed during that timeframe.

What is your evidence that it has been like that for a long time? If anything in the past people were a lot more immobile which means it would be easier for them to eventually make new friends over time.

Considering the evolutionary argument, what happens is the opposite of what one would expect - when people are getting old they are more in need of friends for practical reasons - failing physical condition. So if there is an evolutionary reason, it's probably a paradox.

It may be true however that people seek more alone time as they get older - our brains become less excitable, less craving of novel environments and people and information etc. That's a behavior that's related to aging however, not evolution.

You're the one who originally claimed it's changed in the last 40 years, so it's on you to back that up.

Re: evolutionary argument. That's not what one would expect. That's simply your assumption based on a simplistic notion of what an evolutionary explanation would involve.

Re: your final paragraph, that shows you haven't been paying attention to what I've been saying. If you read my comments you'll notice I've said "biological or evolutionary", and aging is most definitely biological. Anyway, you're wrong to assume that has nothing to do with evolution!

i can point you to the absense of literature talking about this lack of post-young-age friendships. For example, while the grecoroman philosophers and the stoics wrote extensively and in detail about friendship , they don't seem to mention any problems finding friends even though they were past their prime when they wrote their stuff. Society was also a lot more gender-segregated in the past, gender roles were separate, which means marriage did not disrupt the social life of men (primarily) as abruptly as it does now. I have no time to research the subject but it 's reasonable to assume that all that, combined with immobility and slower pace of life contributed to someone gaining more friends as time goes by instead of losing them.

Perhaps it would help your argument if you provided counterarguments to others instead of just dismissing them. Pretending to speak from authority weakens your position.

You still haven't provided any evidence that it's changed in the last 40 years, and clearly the philosophers you cite are completely irrelevant to that claim.

Re: counterarguments - or how about you don't make confident assertions about topics you're clearly lacking a solid grounding in (for example, your comment shows you don't understand that evolution operates on the level of genes rather than individuals) -- where you must know you're lacking that grounding -- and go and learn a bit more about it yourself rather than demanding that others provide you that education? I'm sure you wouldn't behave in this sort of way if it was some other topic, like something to do with computing.

you are evidently unable to form a counterargument, so i can up make one for you:

It is possible that evolution might have made it so that older people do not have friends, so they die sooner and thus consume less resources from prime-age people. The older people are past their child-making age, so they can't affect future evolution in their favour. It's odd however that people did not complain about this until the latter half of the 20th century , or that men did not escape this fate (since men can have children even at old age).

i do not back this up with any evidence though, since you 'd dismiss it as irrelevant anyway.

As I've already pointed out, you do not understand that evolution works on the level of genes not individuals. You're reiterating that ignorance here.

Other parts of your really basic lack of understand of it is also demonstrated by your latest comment:

- thinking that evolution works as if it had intention and foresight.

- thinking that being past child-making age can't affect "future evolution in their favour" (this is a variation on the misunderstanding that evolution operates on individuals rather than genes).

There's nothing wrong with being ignorant about a topic, but there is with being so and acting like you know what you're taking about.

The hypothesis holds in the population level as well: populations that evolved to disadvantage their older members might be more successful.

I dont care if you keep insulting me to make your point, but for the sake of conversation, dont assume your assumptions are correct

They're not intended as insults, they're intended as objective statements of fact that your understanding of evolution is based on misconceptions

And BTW, this new comment of yours represents another elementary misunderstanding of evolution, that of assuming group selection (despite some contested arguments for specific cases of purported group selection, no one agrees with such naive group selection).