I don't even get my Subway salad chopped as I am not a fan of chopped salad (too mushy sometimes). They just layer it into the container.

I think one reason fast food places don't have many salad options is the extra ingredients. Sure they have lettuce and tomato and onion for the burgers, but not cucumbers, celery, peppers, etc. It would be stocking the extra produce which also spoils faster than meat, cheese and buns.

Subway though already has the extra veg for their sandwiches.