Pre-20th Century Gadgetery
The Byelorussian Hatter writes "Wired, presumably bored to death of Cellphones, Zunes, MairBook Nacs and what-have-you, looks back at the elegant inventions of a less civilized age. 'The Turk was a chess player concealed in a table packed with cogs and gears, contrived to give the appearance of a mighty chess-playing machine. Atop the table, an articulated automaton would be seen to make the moves determined by the master within. One of the 18th and 19th century's many illustrious hoaxes, the Turk is perhaps the greatest gadget that wasn't.'"
Then I realized that it isn't me doing any of those things. Someone else built my heating and cooling system, and my plumbing, and ventilation. I'm really no better than a caveman--I just found a much nicer cave to move into.
Hunter-gatherers (still present today in various locations around the world, btw) spend approximately 1/3 of their day looking for food--just surviving.
Modern office workers (still present today in various locations around the world) spend approximately 1/3 of their day working so they can pay for their food--just surviving.
"Beware of bugs in the above code; I have only proved it correct, not tried it." -- Donald Knuth
Let's not get all excited by this "royal we" concept. Some of us can slaughter a cow - you need not be a medieval peasant, just someone who grew up or has worked on a farm or ranch.
I think your premise is a bit flawed. Clearly, as a society or race or species (however you choice to enclose large groups of humans) "we" understand and can manipulate much larger bodies of knowledge than say, a medieval priest or even royalty. But on an individual level, this is also true. Lots of folks I know can slaughter a cow, at least pretend to fix a microwave, certainly fix an internal combustion engine, use a complex piece of electronic equipment (and I'm not talking about an iPod), shoot a gun, etc. recall the quotation from St. Heinlein:
Faster! Faster! Faster would be better!