If I could go back in time and change the Dungeons and Dragons and Philosophy anthology in one way, I would make sure that it included an essay on rules bloat.
Nearly every role playing game suffers from this. At the outset the impetus is to present something that is easy for new players and game masters to figure out and play. After the game hits a kind of popularity threshold the only way to make new money on it is to produce expansions with new character classes and rule-based mechanics. To get people to pay the money, there has to be some sort of ludological advantage to using the new characters and mechanics. So if you just stay with the old set, at a minimum your characters will be underpowered.
But each expansion makes the game more complicated, until it finally reaches a point where it becomes borderline unplayable for everyone (except for the Simpsons Comic Book Guy who loves this kind of thing). And it gets so slow. Where you could have had twenty combats a night in the unexpanded version, now you can only complete two, and you spent long increments of time thumbing through various books figuring out the proper algorithm for how the dragon-spawn Barbarian's grappling ability works during attacks of opportunity when the opponent is half submerged in water.
Since the industry needs non-Simpsons Comic Book Guys to remain viable, a new edition* is then released, and the process starts all over again.