If you become a vegetarian in the US, you will come to appreciate that almost no mains offered in any "American" restaurant are without meat. If you go to a popular American restaurant that your friends picked, you are lucky to have 1 non-salad non-side option.
For whatever reason, our culture has decided that if it doesn't have meat, it barely qualifies as a meal. As a result, high quality vegetarian food must be aquired by seeking out ethnic food, seeking out veg friendly places, or learning to cook.
I've never understood the need to use a replacement that's worse across the board.
I wonder if it's a cultural thing, like "I want a steak"