And furthermore, much of the work and reading material (especially in the social science, not sure about other fields) is really about jumping through hoops, learning the game, knowing the rituals of your particular tribe, and knowing how to cite other academics so that you can properly join the social network. If you are just trying to learn for the sake of knowing, 95% of the readings and the problem sets are irrelevant.
A PhD has _nothing_ to do with coursework and _everything_ to do with conceptualizing, managing, and completing projects then finally _communicating_ the results. Yes, it's about original research, but that usually doesn't mean that it's done in isolation.
Yes, you need to be conversant in your field. Yes, that means being up to date with what other people are doing. At the end of the day, though, the key question is, "Can you convince other people to buy into your work?".
A large part of it, for better or worse, is salesmanship. (Also know as "communication".) That's by design. If you can convince several intelligent, skeptical, and yes, biased people that you are right, then there's a good chance that you are.
People are human. They have agendas. It's not a perfect system. Nonetheless, peer review mostly works. I think there are things we can do to improve it, but the picture most people seem to have of academia is overly pessimistic, i.m.o. I would argue that it works fairly well, for the most part.