For 1, the data is based on guessing, so it’s zero surprise that self-perceived ability doesn’t correlate perfectly with actual ability. It would be extremely surprising and unbelievable if the slopes were the same, right?
For 2, the DK paper shows one thing, but the replication attempts have show this effect doesn’t even exist for very complex tasks, like being an engineer or lawyer. The DK effect doesn’t generalize, and doesn’t even measure exactly what it claims to measure, which is why we don’t need to speculate about the bizarro-DK reversal effect - we already have evidence that it doesn’t happen, and we already have a big enough problem with people mistakenly believing that DK showed an inverse correlation between confidence and competence, when they did no such thing.
For 2, the DK paper shows one thing, but the replication attempts have show this effect doesn’t even exist for very complex tasks, like being an engineer or lawyer. The DK effect doesn’t generalize, and doesn’t even measure exactly what it claims to measure, which is why we don’t need to speculate about the bizarro-DK reversal effect - we already have evidence that it doesn’t happen, and we already have a big enough problem with people mistakenly believing that DK showed an inverse correlation between confidence and competence, when they did no such thing.