>>>If my technique was not efficient , I could not make it, what with diminished core strength and musculature.<<<
Thats my secret, skiing efficiently. at 76 I'm only three years behind you and still have two good knees, (even if my wife Ann doesn't, thanks for your advice, she just can't bring herself to do knee replacement)...The shaped and shorter skis have helped a great deal.
In my prime, my domain was the fifteen feet from the edge of the trail, better snow less crowded and easily ski around folks standing on the edge. Not any more. Though I am very secure on my skis, one oopla could have me kiss a tree. Likewise I avoid the moguls unless I can't avoid them, with a little planning avoiding them is easy, though. I ski between 2-4 days a week and a three week vacation of skiing almost every day, blizzard days I don't enjoy anymore.
While I'm at it, A couple of weeks ago a group of my old time skiing buddies were at a supper and I took an informal poll and the result were:
75 to 80 year olds, mostly retired ski instructor and patrollers had confidence problems, despite skiing all they skied before, every time they start they have doubts and are surprised that they had no problems skiing it. My former ski school director, now in his 80s, and a super skier in his time gave it up because he said: "I am scared to ski fast and I don't enjoy to ski slow, so to hell with it".
Other issues were medical, reduced eye sight or depth perception, some loss of balance at times, and mostly strength.
One issue that came up is that is often perceived as too much to have to put on the layers of ski clothing, drive to the hill, carry in the skis and ski bag, putting on the boots, etc. but once that is done and they are on the hill it all is worth it.
And lastly, they look at the weather forecast and pick a nice day.