Well, yes - but a preponderance of distracted walkers isn't a argument against smartphones. It's an argument against cars. If somebody uses a dangerous device in a public area, they are responsible if they hurt someone. If a certain category of dangerous devices is implicated in the injury of a lot of people who were in public places, then it should be banned.
I know cars hold a special place in the mythos, but I think they are a bit like alcohol. They have basically no upsides, and if they were invented today, they would be illegal, except for professional or industrial purposes.
I don't own a car, and rely mostly on public transit, but "they have basically no upsides" is just bullshit, sorry.
They can transport a group of people, plus significant amounts of load, together, quickly, in relative comfort, at any time, directly from/to a specific place.
It's not practical to have acceptable public transit everywhere and to use it for every purpose.
> a lot of people
~4k out of a population of 320M is not a lot. That's less than what smoking kills in a week. Or, if you look at it differently: assuming a life expectancy of 80 years, if you inconvenience 320M people by two minutes a day, you have taken away a total of ~5.5k human lifetimes from the population.
Well, everything has upsides if you don't compare it to the competition. Even if cars were incapable of transporting people, you could say the upside is, they're a good source of scrap.
But, compared to the competition (buses, light rail, bicycles), it's hard to see where cars come out ahead. They are more expensive than every other option, they produce poisonous fumes, they take up enormous amounts of space, they only work for able-bodied people, they are loud, dangerous, and absurdly wasteful.
I don't think they are worse than smoking as a public health risk. But when you consider the amount of pollution they produce, it's likely comparable. And smokers are taxed - while car drivers are massively subsidized.
I know cars hold a special place in the mythos, but I think they are a bit like alcohol. They have basically no upsides, and if they were invented today, they would be illegal, except for professional or industrial purposes.