Why is catering more expensive than going to a restaurant?

Essentially we are creating a restaurant for you, for one meal, one time. We have to deliver everything to you (vehicles to maintain, travel time), set up the room (many times setting up and breaking down all tables and chairs), bring in all linens, dishes, glassware, etc., and chefs and wait staff – all just for you and your guests, and return everything to where it started. None of these costs are part of the restaurant scene.