Probably very difficult to automate because cooking is so full of variables. Ingredients, even by the same brand, can differ massively. Like flour, eggs, yeast and the like can be quite different. Then specifically when it comes to baking the room temperature can affect the outcome a lot. Assume it's very hard to make the robot assess the probable outcome during the process to sufficiently tweak it enough to make the end product come out great. If a human pizza-baker starts pulling at the dough and notice that it's not as supple as it should be then heshe will tweak their handling of it or process it further. For a robot that would be quite difficult, not impossible but difficult.