Well, in terms of just technology - in Europe at least, there definitely was a constant, gradual and largely never reversed technological development ever since the Fall of Rome / the start of the Early Middle Ages. That was definitely a developmental low point, but ever since, 1500 years ago, there has been constant technological progress. After all, we shouldn't think that all pre-industrial periods and societies were the same. Even before industrialization, there were
huge technological differences. The early and high middle ages saw astonishing progress in agricultural technologies, which was of course absolutely necessary to feed the population (of course, even so, the 13th century was a Malthusian catastrophe). The late middle ages saw astonishing progress in such areas as metallurgy and administrative and trade techniques. The baroque and enlightenment had all those developments in mathematics, physics, astronomy, chemistry, construction, etc etc. That all happened already way before Industrialization.
So in terms of technology, at least, there was no "take-off" point. It is just that the more technology you have, the better conditions you can create for further technological advancements - i.e., the more technology you have, the faster you will get new technologies. It is a speeding up process - and there also is no time when it "began" speeding up, it simply gathered gradually more speed as it went along: Like an exponential curve. The speed of development in the High Middle Ages was unheard of in the Early Middle Ages, but was easily surpassed by the Late Middle Ages/Renaissance, which were easily surpassed by the Enlightenment, which was absolutely cast in the shadow by the industrial 19th century, which was further surpassed by the speed of developent in the
20th century - and so on and so forth.
There is no great secret to it, no "clue". It is just technological development gradually gathering steam and getting
gradually ever faster. And that, in Europe at least, for 1500 years now.
Of course,
social development is another matter. There, we have only seen a constant and uninterrupted development towards more liberal, egalitarian societies since the 18th century. Before, you had ups and downs. The flowering of 13th century court culture and the vast overpopulation of Europe meant labour was cheap, the lower classes exploited like never before in the early middle ages, and society stratified like never before - but that was 'remedied' by the 14th century population crash (Black Plague, 100 Years War etc), and in the 15th century, when population had actually further fallen, labour was in high demand, the common population was doing okay-ish and commoners were able to raise to academic, financial, administrative position in ways unheard of before... but that didn't last, and the 17th century baroque was the time when exaltation of nobility and class stratification was taken to its most absurd heights yet - which then was reversed again by the rise of the bourgeoisie and the Enlightenment.
So in that regard an up and down, but the current up also is lasting for 300 years already.
I do not think getting rid of the mundane complexities that currently plague me would leave me any worse off, only within the medicinal field which is hard to combat was also morbidly primitive even just a century ago. Men lived to their eighties even back during Classical Greece, which of course was an advanced civilization, but it is not like it is impossible to die of bad health in today's age. Nor is it even entirely reprehensible in many cases.
I am sorry, but you are naive.
"Men" did not live to their eighties in ancient Greece.
Some very few men did. Nowadays, the average person can expect to get
at least 80. It is projected that people born right now can expect to become 100. Not as some statistical outliers, but as the norm! And what about child mortality? The
majority of children dying off before they could become adults!
And that is, indeed, just medicine. What about the constant state of malnourishment for like, 90% of the population? Common people in pre-industrial agricultural societies lived constantly at the very possible physical minimum of existence even in good years. In bad years, there were famines. Malnourishment was commonplace, even common clothes were a luxury, which is why in the middle ages most common people had just two sets of them. Hell, even wooden cutlery was basically held on for life. And even before the Black Plague, epidemies could routinely wipe out large parts of a regional population. And of course, the daily life consisted of bacbreaking constant work.
Can you really imagine that? A life consisting of constant hunger and constant work, huddled together in small, drafty huts, always people around you dying due to illness, hunger or just so? And then of course also, rule by what were nothing more than robber barons, your last grains taken by them as is their right, and also very frequent if not constant warfare - at the very least simmering low-level warfare that will destroy your harvests and what few possessions you might have, but now and then also wars that make that in terms of population
percentages dead dwarf WW1 and WW2.
And you want to romanticize those affairs?