It is true that random boss fights are a common trope of RPGs, but XIII almost parodied this concept. In Chapter 13, which itself is entirely random, you are at completely random points, even mid-room, teleported to a different room to fight a random scary creature, and then just teleported back to continue on your way.

As Elpizo pointed out, there's only a couple story-related boss fights. Hell, you're not even introduced to the main overplot until Chapter 9 or so, making it unsurprising there's nothing developed to fight beforehand.