My first thought is that perhaps it's because they grew up watching the television show, "Cops." That show has created the expectation that robbers run.
Yet, if this is true, then Cops would also create the expectation that robbers who run, get caught - every time. In fact, I have yet to see an episode of Cops where they end the episode looking around saying, "Crap, we lost him."
I'm not saying this doesn't happen. But these episodes never air. So, there is no encouragement for the robbers to run. Unless you have 2 strikes against you, adding "reckless endangerment" to the charges simply isn't worth it.
Why don't these high school dropouts understand reason?