The funny thing about "smart" cars and "dumb" drivers is...
Back in the old days, there were no airbags or even shoulder belts. Cars didn't have ABS... which didn't matter much, because they didn't have much in the way of brakes. People drove around in heavy, rattly deathtraps that had more motor than suspension or brakes (worth mentioning twice). Old tires with weaker sidewalls would not deflate slowly. They'd simply tear themselves to shreds when they popped. Good luck controlling whatever came next.
Yet...
People didn't really care about proper follow distances back then. They didn't always drive within the limits of the car or instinctively back off in the rain. A lot of drivers back then were just as stupid as a lot of drivers are now. The only difference is sometimes they died before they learned better. We remember things differently because we were the ones who learned and survived.
Maybe there's a statistical difference in driver behaviour when they have safety devices. But it pales in comparison to the statistical difference in overall crash fatalities between then and now. And in the end, results count.