Leaded brass plumbing fittings phase-out

Used to explain why leaded brass was historically standard (machinability — lead inclusions act as lubricant during machining, 5× speed advantage) and why it's being banned. Connects to lead-tin solder ban (1978 Massachusetts).

My house is 85 years old, and I had a lead drainage pipe in the laundry room when I first moved into the house 40 years ago. I got rid of it. But I'm not drinking out of that water. Nowadays they just outlawed even lead and brass. A lot of the brass we use in plumbing, like a fitting like this, ten years ago would have been made out of leaded brass. Can't do that as of next year. They're going to have non-leaded brasses. Does anybody know why we use leaded brasses?