I have a friend who's very low income and rides a second hand ****ty dual suspension big box MTB because he lacks a car. We were talking about riding, and he hangs on the sidewalks, salmons, rides through grass, etc because he's absolutely terrified of being on the road and getting hit. You don't get any rider education when you buy a bike from a pawn shop or wal-mart. No one tells you to get some lights(Or hi-viz). No one explains the potential dangers of the sidewalk or salmon. It doesn't help that it's hard to feel confident about your vehicle when it's creaky, the brakes barely work and in general **** condition(As most pawn shop rides are).

It's just an education thing mixed with confidence issues. I know there are some bike shops in town that don't bother with education or advice either, just sell the suburbanite their trek that they're going to ride up and down the street, their stock set of accessories, and hope they never come back for their free tune-ups.