I don't know, perhaps you are extrapolating from insufficient data (that is what my old sociology prof used to say). As far as I can tell, all my single mid-life female friends have very strong female bonds with other single or married women, doesn't seem to matter. But they have dinners together, talk to each other, help each other. I do notice however that the driving force in bringing them together for social events is usually one of the single women, and not the married ones (inertia perhaps?).
And speaking as a devoutly hetero male, most of my friends are female, colleagues, allies, etc., 95% of whom I have no interest in intimacy with. They are just interesting to be around. The problem with hetero males is mostly other hetero males: most of them (extrapolating from insufficient data) of my acquaintance do not cultivate their friendships -- they don't feel the need to reconnect very often, and aren't big on exchanging information. They seem to be able to cope -- especially as time goes on, and they have been or are now single -- with being on their own as the "default". This has its positive points; still.....My suspicion is that many straight midlife men are just clumsy in working towards friendship with women -- they can't handle the signalling system. I would say that the secret key might be to find out if they grew up with one or more sisters!
Of course, the most important thing is to like being around women. You need to find them more interesting than men -- but that isn't hard.
Toronto--
I was not sure if you saw that I was, myself, a female, (Kelsey is sometimes a man's name)-- asking other females for their perspective. NOT that I don't appreciate your efforts, and your wonderful responses--- but I am fairly certain this is a "female" problem, of which men may know from the outside looking in. It has to do with "woman to woman" dynamics. Now I don't diminish the fact that men over 60 may indeed have a hard time making friends, but the issues why are different.
Definition of Friends: someone you can call up & have lunch with, someone you go to a movie with---not just an e-mail buddy or a person you are cordial to at the office. Someone you would invite for Thanksgiving or give a birthday present to... I know men say they have loads of women "friends" with no intimacy--- but the activities are usually at work, or an occasional e-mail, or a buddies wife--- never a "one-on-one" outing.
Never a "one-on-one" outing? Stand corrected! Yesterday I had a one-on-one outing with a female friend of long standing that included shopping, getting a massage at the same place, taking dinner and watching a movie. Not long back I had another close friend who was a woman. (I speak in the past tense because our lives have changed radically and it has become almost impossible to meet as often as we once did. We first met when she became my deputy in work, but the relationship quickly developed beyond boss and deputy but there was never anything sexual in that relationship either. We became very close friends, platonic friends - could talk about anything. So close she used to refer to me as her "husband in the office" and her husband, the "husband at home". He knew and was amused as me when she called either of us by the other guy's name. She and I regularly met up socially for meals out or drinks - just us - sometimes propping each other up after a few too many drinks! We just enjoyed each other's company, not each other's bodies.