It isn’t just how fast it is or how much range the vehicle has. Think of police vehicles as
the most abused rental fleet. Different drivers often going places you would never take your car. Throw in people that are arrested & often belligerent & you have cars that wear out quickly. It isn’t just the miles it’s the abuse necessary to do their jobs.
On occasion they need to sacrifice their vehicle to stop drivers. There is a video on the YouTube channel Wham Bam Teslacam that showed an incredibly brave Oregon State trooper stopping a wrong way driver with his police SUV. The police vehicle was wrecked but he stopped the wrong way driver got out & arrested him. Notice that the SUV’s air bags deployed likely totaling the SUV. Had his timing been slightly off there could have easily been fatalities. It’s those possible events that make police wary of changing what they drive. They are even going to change over to EV’s but it’s going to take time.
Here’s a link to the video: