Most likely.
$0.075 per car? Ha, so that is what PD get paid for investing a month modelling a car!
That's unfair. Based on your thought, perhaps as the game has 15x more cars than your average racing game, it should cost $900. Don't take the size of the game for granted.
I think the pricing should depend on how many copies of the game they sold and roughly how many units of that DLC they expect to sell. That would be more fair. But I guess people need to be paid and some get greedy.