Earlier quoted context omitted.
I could explain it, but it's easier to just show you an example. A game designer writes things like this: http://www.squidi.net/three/
Coming up with new game ideas is the holy grail of game design, but a game designer's day to day work is creating and refining game content, often working with programmers to tweak the implementation. For instance, take Super Mario Bros.: the developer would write the graphics rendering code, physics, make a level editor, etc, but it's the game designers who decided beforehand what the concepts would be, and work aft…
game design : fun :: computer science : information
It's important to make the distinction: fun doesn't only apply to games. A ludologist would be perfectly at home in UI design, for example, or education (and also obviously things like toy and amusement-park design.) You could hire a "game designer" for those positions right now, but people would look at you funny because the branding's wrong.
However, just as there's a difference between computer scientists and programmers, there's a difference between ludologists and the risen-through-the-ranks game designer that we see today, so it wouldn't be a perfect fit. The game designer may know some facts about how to make things fun, and have some theories as to why certain game design patterns produce fun, but they've been "hard-won" on the street; they've never formally studied it, mostly extracting it from their practice in other game-related disciplines (art, coding, level design, etc.) That kind of game designer is half-developer (or artist, or playtester, or what-have-you) working in a sort of cowboy fashion to advance the field.
Of course, ludology is in its absolute infancy (it's about 20 years younger than formal Computer Science) so it's still not even recognized as a separate discipline; thus, the only ones working on it are making their advances in the field, similar to the original computer programmers who had to be Computer Scientists, because no one had thought the thoughts they needed to think to base their work on.
As I said, I'm taking CS and English courses. Tack on a bit of psychology and sociology, some media history courses, and whatever it is that teaches game theory (economics? basically, "fairness" as it relates to fun), and you'd have a good starting program for the actual teaching of formal Ludology. I was always thinking about being a CS professor one day; I might have to change that plan a bit, and perhaps write up my own curriculum ;)