Incidentally, the lead wasn't really being mined to make lead pipes. They mined galena for the tiny amount of silver it has and got tons of lead from that.
Because all of human progress is just building on top of what we've been able to find, then using those things in combination, and those things, and so on until you get to super evil chemical manufacture. Seems like an arbitratry line?
(For what it's worth I cook a lot and buy very little that isn't a 'raw ingredient', I'm not saying this from a 'let me have my ready meals' sort of perspective.)
More relevant to the sokoloff's point is the fact that extraction of lead was not done for the sake of plumbing, it began thousands of years before lead pipes were invented. There wasn't a point where people were weighing the harm of extracting lead against the utility of plumbing; the lead was essentially a waste product of the silver industry.