Where I come from in Southwest FL all of the cars have cages (we called them screens) and this was at small departments and 800+ deputy departments as well.
I remember when I came to Oklahoma for the first time about 11 years ago. I started at the police department in the town where I lived and everyone transported prisoners in the front seat. I was shocked. That would have gotten a guy written up pretty fast where I came from. Kind of like cuffing prisoners in the front...it's just something you don't do unless there is a VERY good reason to do it. Fast forward 11 years and guess what...that same department STILL transports prisoners in the front seat.
Sure, they've lost some equipment and had stuff damaged but I guess not enough to justify the cost of cages. It's all about the dollars, not about officer safety.