But beyond child mortality, here's another example that regulation does impact: traffic deaths . Government regulations surrounding car safety, seatbelt use, airbags, etc have had a massive impact. Looking at the data from 1970 (a time when older HNers would say "when I was young") to today, there were 4.74 deaths per 100 million miles traveled, compared to 1.16 today. And even as the US has added 120 million new Americans to the population since then and vehicle miles traveled has basically tripled, not only have we reduced deaths per mile traveled, we've reduced deaths period, without worrying about normalizing the data to population or VMT.
I hear quite a bit "when I was young we didn't have seatbelts or airbags and we rode on the back dashboard and didn't have child seats and we survived just fine" except a lot of people didn't. A lot of people died, and that's why regulations were created and that's why fewer people are dying now.