Not just vegetables, also hash browns, fried potatoes, french fries, pancakes, spaghetti, etc.

There are plenty of vegetarian meals (or vegan ones, though that's harder). It's just that we have relegated most of them to side dishes, entres or breakfast because meat is too popular as a main dish. But this is a very recent phenomenon

But you can't make any money selling hash browns as veggie food, it's much more profitable to sell fake meat