Yes, Eric, and I think that Sarah Moon knew this long ago because in one of her online musings she says that she feels this heavy responsibilty to catch the model's beauty now, before it's gone for ever; that she feels this terrible sense of time flying past and that what she thinks she is seeing might not really exist at all, only during part of the gifted moment as she gazes through the camera. I think she is perhaps right: physical beauty itself does change over time, never mind magical moments on-camera that nobody can create the same twice. I do recall my wife saying once that it was so unfair, that aging men could grow into a "distinguished" sort of look/style but that women just went to bits, and the more artifice they employed to disguise, the worse they made themselves look.
So, yes, surviving good looks do depend on something other than youth as time leaves the old pages turned forever, and I think that insofar as the physical bit goes, facial bonework is key. And so is whatever chemistry prevents facial fat from forming and sagging downwards and dragging the lips and cheeks with it. I suppose most men find it around the waist instead (their waist, I mean), and it gets blamed on beer or whatever.
It must be terrible to have youthful beauty, know that you do, make a fortune from it, and realise in your twenties that it's going slowly away from you and you can't stop it. Should you?
It brings to mind the positive or negative values of keeping photographs. Is it better, in your later life, to have images of yourself shot by some of the best people in the business, make-up by top artists etc. etc., even if you can admit that the image is only based on yourself (now more so than ever with digital), or does happiness and peace come from not having such reminders of other days?
Regarding the remaining model I knew from the 60s: she turned up out of the blue one day a couple of years ago as I was shooting some guys in a bar during my "musical period" (a joke - it only lasted a few months because it was ever the same old faces and one group) and I thought she looked familiar but I had no idea why. She knew me at once, despite the lack of hair, and came up to chat. Turned out she and hubby come over for a couple of months every winter to escape Scotland's worst. I asked her to do another shoot, just for old-time's sake, and she managed to avoid it ever happening. She was far more perceptive than I. And she was right: being in one's sixties defies everything, even the best bones ever.
Rob