Where things get interesting is when you look into why it is they are becoming necessary and start speculating as to whether or not it is a trend that will continue. These private security firms are necessary on the streets due to failings of the city/state to provide a necessary service and are stepping in to fill that void. If the trend is extrapolated and state police continue to struggle then there is a genuine chance these private entities will become the de-facto police, a corporate police force for hire.