Funny enough my only bad grades in high school were with languages, I think your analogy is apt. I could understand bio and learn it but performing at the level needed to be a doctor was not going to happen. Although, I have no regrets very happy with where I ended up!
Doctors aren't actually that good at their jobs once you start recording patient outcomes. It probably makes no sense to continue the current method, but the AMA is the one that controls it, and making it hard makes the value of their labor more expensive.