Paul, this observation is not a borrowed thought. And, I wish you did some basic research like Semiman below. Perhaps, you did not have the opportunity to actually see how much more healthier our own ancestors were, only a couple of generations ago. My own great grandfather could still walk farther and had stronger teeth than some of our generation. And we are looking only less than a century ago. They don't appreciate medical attention and still don't fall sick as often as we do. Does having medicines for all you are suffering from make you a healthy person?
As far as cavemen are concerned, true that life spans were far less and deaths were mostly due to serious injuries or illness. But, I would trade 20 years of my lifespan any day if I could live a better life for 50 or 60 years. Protracting one's lifespan is not an indicator of quality of health. You would be less and less vital. Now, that would be living like a parasite. And btw, would you not love to be a strong, pain enduring bad ass with a natural talent for survival?
I am going to defer to a litte paleobiology theory that theorizes that the ancestors to humans really started to take off when they developed tools that allowed fishing and other successful hunting and by correlation greatly increased our intake of amino acids fostering brain growth ... which lead to all the other great inventions over time.
Actually, they did not die toothless. To die toothless was a more modern "invention". Cavemen lived on a diet of meat, and foraged plants all low in carbohydrates. Hence no tooth decay. It really wasn't until we started farming that he had tooth decay.
Agriculture is the single biggest step forward. A regular supply of surplus food made it possible for people to think about something other than where their next meal was coming from. For the first time specialization became practical and from that came civilation.
The sciences (mathematics, astronomy, civil engineering) and organized warfare are a direct result of agriculture.
Mathematics arose to be able to keep track of food supplies. Astronomy to better predict the correct time to plant and reap. Civil engineering started with canal building.
Warefare as we know it is entirely a product of agriculture. Prior to agriculture, warfare basically consisted of hit and run raids looking for portable loot and wives. Agriculture both motivated wars of conquest and made it worthwhile to resist. Cities grew because they were mroe defensible.
Heard Fritjof Capra on the radio saying this morning, that what enabled homo sapiens to conquer the planet was not superior weaponry but better networking.
So the technologies that help networking are the ones...horseback riding, the wheel, writing...coffee houses...facebook...twitter...newspapers and printing.