Vegetables in cat food.

I honestly don't ask this to be contentious; I really don't understand. Why are there vegetables in cat food? To the best of my knowledge cats have been carnivores throughout history. I can't imagine a cat in the wild chowing down on carrots, peas, and pumpkins. I've asked other cat owners as well as my vet, and the consistent answer I get is "Well, it won't hurt them". What kind of rationale is that? Is it that the domestic cat has, over time, morphed into a different kind of animal with different nutritional needs, or is it just a cheap filler that cat food manufacturers can get away with using? 

I know this subject has been addressed before, and I did a forum search, but most of the questions and answers seem to deal with which vegetables were best, not why they were in the food in the first place. I've been making it a point to shop for foods that didn't include vegetables, but if I'm missing something I'd appreciate the feedback.  Thanks.

Personally I feel that the vegetables are part filler and part to appeal to a Human's perception of healthy food aka marketing gimmick. Cats don't need vegetables and fruit in their diet. But many commerical cat foods contain those things so it's impossible to avoid it.

Companies need something to fill up the can and increase their profits. Peas are inexpensive and readily available.

Thanks for the feedback. Hadn't thought about the human perception aspect, and that certainly makes sense.