Why is competition law one of the most prosperous subjects in academia?

... because you can become a prime minister. Mario Monti the freshly elected prime minister of Italy is the former European Commissioner responsible for competition policy. His short bio from Wikipedia can be read here. (By the way, Wikipedia needs donations to be free and alive. See here.) His carreer is probably closer to academia than to anything else. Good prospects ... but mixing competition ideas with politics is not a good and popular idea. (I am not involved in politics apart from being a competition law teaching academic who is also a voter.)