The Pregnant Widow: last funny in 1970?

"In evolutionary terms, this guy say,s breasts are there to imitate the arse."
"The arse?"
"The breasts ape the arse. As an inducement to having sex face to face. When women evolved out ofoestrus. You know what oestrus is?"
Keith knew. From Gk oistros 'gadfly or frenzy." Heat.
Whittacker said, "So arselike breasts sweetened the bitter pill of the missionary position. Just a theory. No, I understand about Scheherazade's breasts. The secondary sexual characteristics in their Platonic form. Plan a for the tits. I understand — in principle..... What d'you guys do with breasts> I mean they don;t lead anywhere, do they."
"I suppose that's true. They're sort of a mystery, And end unto themselves."
— The Pregnant Widow, Martin Amis

Here's what I think of that. If I heard some male friends having that conversation I might laugh. It is kind of funny to hear clever dicks being clever and dickish sometimes, if they're your friends. If, however, I read that in a novel its humor would decrease at an exponential rate: no longer the momentary flourish of jousting wits, it would instead come across as merely pre-rehearsed, even a little smug. Set the novel in 1970, and the point is definitely beginning to feel past its sell-by date. Sorry to be so down on Amis. I'm sure the book is going to be great. Just needed to clear my throat.