When does baking/cooking in bulk have an advantage?
Mostly, it's just more efficient from a time perspective.  You can do all the stuff that a restaurant kitchen does at home on a smaller scale, but it may seem like a lot of work for just a small portion.  

For example, the prep time to make homemade broth, then put together ingredients and cook a homemade soup for 4 servings might take you most of an afternoon.  Maybe by adding an extra hour for processing ingredients, you could easily make 100 servings of that same soup.  The difference between making 1 loaf of bread and 20 loaves of bread is minor, assuming you have equipment to handle the larger quantities.  You'll spend a few more minutes dividing and shaping, but otherwise most of the time is just waiting for the dough to rise and then bake.

So it's really about efficiency.  If a recipe says "stir for 20 minutes while simmering," you'll probably have to do that for roughly 20 minutes whether you're making a cup or 3 gallons.  And because all that prep work is tedious for just a few servings, many home cooks won't bother -- they'll substitute store-bought broth or bullion, they'll buy pre-mixed bread dough, etc.    Those "shortcuts" are often one main difference that can make your home cooking not as good.  Otherwise, there really aren't specific advantages for most dishes.  In some cases, you may need to adapt techniques or recipes to handle larger vs. smaller quantities.  But flavors can be effectively developed in most dishes whether you're making one portion or a hundred.