It's not violence from the job but their job was generally bad for their health in other ways. Sitting all day without getting up and driving around with windows down getting all this UV.

Also, older ones were exposed to a ton of cigarette smoke.

I'm gonna go out on a limb and say that not even a double digit percentage of taxi drivers' careers are ended due to violent attacks. Taxi driver doesn't even appear in the U.S. Bureau of Labor Statistics top 20 most dangerous jobs.

That's like, almost all of them.

survivorship bias