Frustrated spinster

In the mysteries I've been reading (which I'm enjoying immensely, by the way), all written before 1960, I've noticed that there is almost always, in the cast of characters, a frustrated spinster. She is usually eccentric, has some kind of obsession (cats!), and generally behaves bizarrely. There are various 'types' of spinsters (bluff and hearty; fussy and prim; coy and sex-mad, etc), all instantly recognisable. These women become particularly erratic when they reach a 'certain age.' Occasionally there is a man (usually unmarried) who is labelled 'spinsterish', and we instantly know what is meant by that.

These characters have disappeared from modern mysteries, and indeed from modern western life. What happened to all the frustrated spinsters? Hellooooo? Are you out there?

Actually I've been thinking of getting rid of The Man and becoming a frustrated spinster myself. (I could possibly arrange to avoid the 'frustrated' bit.) It seems a pretty attractive life to me. You can do what you want, because no matter how bizarrely you behave you are tolerated (well of course, she's a spinster, poor dear...), on the fringes of society at least. A sort of honourary member of society, with a recognised rôle.

And what better place to be, than on the fringes of society?