Terry,
Your account of truth, estimates and the indefinite 3rd person plural - laugh out loud amusing. Reminds me of some property I owned for a number of years and finally got rid of. I could just see the trench in the front yard and the incoming new repair estimates lobbed in like hostile mortar shells.
Regarding things like, "You know what they always say..." It was other activities of decades back that used to stick to the back of my mind:
"You know what they are doing now?..." "Do you know what they are working on now?..."
This was the stuff of monorails and trips to Mars. Devices that I should have noticed in Popular Science or Popular Mechanics. As one social commentator remarked, it was akin to invoking a great conspiracy to make life better for "us". Even after two world wars that sort of optimism still remained in many areas of the country.
It might be that the estimates on things like spaceships and fusion power seemed to extend out like that plumbing job. Or maybe increased deficit spending made it harder and harder to follow up on all those research initiatives assumed by the Great Society, etc. In any case a whole lot of "advancements" did sneak in the back door. I say "advancement", because I am not that keen on app loaded pocket telephones that you can stare at all day, but I do appreciate what can be done in a day's work based on data.
Then sometimes one gets involved in a new project and you begin to wonder that maybe you might be working along with some of the group that people might be talking about - "You know what they are doing now..." Well, actually...
... The notion of "what they were doing" did invoke a notion that life was getting better, just like Victorians or Edwardians might have thought - until that frame of mind came to a screeching halt 100 years ago. But this was not the first time that had happened - or that society recovered from it.
It just might be that life on this plane, whether it gets better or not, will keep on going. It will change to a form that fits the aspirations of our children and grandchildren more than ours, descendants that like apps more than I do. And just because we do not like the prospects, does not mean that iall has to end.
Another "estimator" of a different persuasion, I think it was Malcolm Gladwell, suggested that we live in a most likely state. And when it comes to the age of mankind, tautological argument, so to speak, leads us to think we are near the middle of its life - since that would be the most likely result of such inquiry. We seem to be located in space and time at a rather arbitrary point after 13.7 billion years of goings in a spiral arm of a typical galaxy... The same might be true about the age of human kind. So if we see skeletal traces of ourselves back 40,000 years, odds are...
But wait, where's my slide rule? 607 BC Jerusalem's Temple was knocked down to crank up a 2520 year cycle mechanism... so that oh so consequently we are privileged to live at exactly 100 years after the clock ran out on that epoch, drawing to the tottering of another massive, momentous, cryptic domino...
"In the world of prophecy do you know what is going on now?..."
What a trade in mindset!