Why is IB so hard?

Why is it that so many people find Investment Banking (IB) to be a particularly challenging field? Could it be the intense competition for positions, with top universities and high-performing individuals vying for limited spots? Or perhaps it's the demanding work culture, where long hours and high stress are the norm? Could it be the complex financial instruments and transactions that require a deep understanding of financial markets and analysis? Or is it the fast-paced, ever-changing nature of the industry that makes it difficult to keep up? Whatever the reasons, it's clear that IB is not for the faint of heart. So, what drives individuals to pursue a career in this challenging field, despite the difficulties they may face?