The vast majority of challenges organisations face are wedded in how they interact with society. If a groups not working well together, is it knowledge and creativity that's the problem, or social and value clashes between members. The vast majority of day-to-day management challenges fall into the latter category, so no wonder management attracts people that are interested in "social intelligence" and we tend to be interested in what we're perceived to be good at.
Having studied both in arts and sciences I would say that both approaches have advantages when applied in the real-world, and limitations. I don't believe (or know of any evidence) that "Arts" people are more likely to suffer the Peter principle. It's a function of seniority that you lose information versus specialists in an area - so if anything it's connected with bombastically believing you're right rather than what degree you did.
Having studied both in arts and sciences I would say that both approaches have advantages when applied in the real-world, and limitations. I don't believe (or know of any evidence) that "Arts" people are more likely to suffer the Peter principle. It's a function of seniority that you lose information versus specialists in an area - so if anything it's connected with bombastically believing you're right rather than what degree you did.