People jaywalk primarily because of bad road design. It's especially prevalent in poor, minority neighborhoods, which tend to be exactly the places that were cut in pieces by large road construction projects in the middle of the last century. The east side (which is the poorer, more African American side) of Greensboro is a great example of this. The historic neighborhoods were chopped up by big four lane stroads, where the crosswalks are 1/4 mile or more apart. So it's no surprise that people don't want to walk a half mile or more out of their way.
FWIW, when I see people jaywalking, they are not on their phones, they're watching the cars and trying not to get killed. The people in the cars are the ones who are texting, talking, and what have you.
I could derail this thread further with some history on how "jaywalking" was invented by automobile manufacturers to establish dominance for their products on the public streets.