Assuming enlightenment is what you have observed in yourself since about the age of 60 (big assumption), I have a theory about that.

I am only 61 so probably not as enlightened but it occurred to me a couple weeks ago that until we retire from the world -- our jobs are done, our families raised, we have the house, the education, the legal voting/drinking age, have had the career, the grandchildren are here, etc.; all that came before was a looking "forward" and now we are in a period of looking "back" because the only really big thing in the future is the, no doubt enlightening, adventure of death. We have quit listening to the current "in" music, sometimes don't know what day it is and often don't know what date :-) and are a bit slower to get the latest technical toys.

Yes, we have interests in retirement, engagements, learn new things, enjoy our lives but the focus of "what next" is pretty much gone? We literally can't look forward so we only have our actual experience from behind us and what we feel it "means" to go on.

Now we can look back and tell the 40 year olds there won't always be the feeling of doing a zillion things at once and feeling one is spinning one's wheels and the 50 years that the tiredness is probably never going to go away again. We can calmly pick out the things we did that we now see helped us deal with the kids, the schools, the obnoxious boss, how to take a minute for one's self and relate those personal tips to those younger than we are. Because it comes from us, first hand, instead of from a book or an "expert" (love those male gynecologists telling women what it is like having a baby :-) it has a different ring to it, an attractive first-person, "knowing" ring that gets thought of as "wisdom" or "enlightenment" :-)

All my "big" life experiences are done and available for my perusal and arranging to suit me, retelling, savoring. Sure, my husband or I may get critically ill and/or die and that will be a new experience but I have been critically ill and dealt with my parents in this stage in their life so have a little experience with others being critically ill and dying. I do not have ultimate experience of this stage in my life yet though, as I'm "in" it. But I don't have anyone "ahead" of me who I want to tell about this stage, wow them with my expertise because everybody ahead of me is in the exact same stage of life.

It's like when your parent told you as a teen you'd understand when you were grown and had kids of your own; you sneered until you were grown and had kids of your own You were trying to move forward, get "ahead", pass the next milestone, understand your life's mysteries before they happened so when they did, you'd have a clue and "do" them right. Well, now most of them are done and they were done "right" because I'm still here!