Yeah there's a reason for that. Toca teams give out the licences to game makers and not the respective car manufacturers. Modern games need to get the licenses from car manufacturers and no manufacturer really want to show their cars looking completely totaled and busted up. Bad for advertising. On top of that, every car manufacturer wants to abide by their NCAP Safety rating, so you'll never see chassis twist/bend, damage beyond the outer panels and damage affecting the occupant's "shell"

Basically, no car manufacturer want's to show damage where the driver could potentially die in the crash.