Yes, because anywhere this might happen will have a ready police station. That is assuming there is one you know about in the areas that have them, which is not a great assumption for many (as already posted a couple times in response here).
So no, not as easy in a great number of cases. Additionally, the same incidents occur outside of vehicles where your advice is completely untenable in the event the punks aren't just fucking with your head.
My girlfriend was mugged in the city of Spokane. After the little assholes ran off (too stupid to check inside her coat where her wallet and cell phone were, she dialed 911. She was told to stay there, and an officer would be by sometime in the next hour. She was 5 minutes from home, so she disregarded their advice to hang out on the street under a freeway overpass for the next hour.
Needless to say, this sort of thing happens regularly here. Since the mugging, she's learned to practice tactical awareness when walking alone at night. Being able to brandish a weapon is enough to scare off most attackers when you can see them coming. A good combat knife comes into play if they get close enough that a safe draw and fire is no longer possible.