Punishing humans does, in fact, prevent mistakes. Or rather, the threat of punishment causes people to be careful to avoid mistakes, and that prevents mistakes. Sure, this doesn't work 100% of the time, but it does work and has throughout human history. Meanwhile, there's no equivalent paradigm for LLMs.

Even if you could threaten an LLM with punishment for making mistakes, you might get longer CoTs, but that wouldn't prevent mistakes in LLMs. The lack of accountability isn't the reason that LLMs make mistakes - adding accountability wouldn't change anything.