They would be truly Epic Crashes if GT5 had debris , semi-realistic collision damanges, wheels coming off, unusable cars immediately following the crash. As it is, there is no fun in driving in reverse , or ramming into AI for that matter. currently, it's like kicking a washing machine in slippers. (note: I don't do that, just laymen speak)
It's fun watching your car fly 40+ feet into the air and the other cars spin out and pile up. Why would I want my car to be completely wrecked after first crash? Unless of course you like restarting races.