"...chronic traumatic encephalopathy (CTE), a degenerative brain disorder associated with repetitive head trauma" was the first thought that came to my head about that list.

Here come some 'maybes'. Maybe we're smarter now and don't do some of the things that used to get us killed. Like hitchhiking, walk alone after dark, jogging in areas we're unfamiliar with, etc.

Maybe the detection right has gone up due to better policing and equipment LEOs use to do their jobs.

Maybe there are neighbors who now keep their eyes and ears open and watch their house as well as neighbors' houses. See something, say something.

Maybe it's a combination of all of these and a few others as well.