The current source of lead seems mostly (maybe almost entirely?) from "lead service lines," which is the pipe between the street and the home. And, new installations of those lines has been illegal since 1986 in the US.
News to me. Do you have a citation for that?
In the San Jose area we get junk mail almost monthly imploring us to buy insurance against the cost of replacing our water lines, because of their age. So I would have assumed that they all get replaced every 50 years or so.
PVC can get brittle, and PE pipe has notorious problems with connectors corroding/failing.
A lot of older sewer lines are clay or cast iron, and they also crack or rust through.
Like wiring, eventually it makes sense to replace them.