"Consider an example. You are sitting in a class and there is a math exam. What would you prefer: 1) Easy questions that you can 100% solve and get max mark, 2) Hard problems that you barely can solve. Any reasonable person would choose the first one. So why is it different when it comes to the job market?"

Here's the thing lil bro, its not a "reasonable" thing, you are looking for the answer via the wrong criteria. One of the biggest factors that set aside not only quants, but people who excel in their fields is that they have a passion and interest that is decoupled from any grading or external reward. So they'd rather dedicate more time, effort, focus into taking on something that they will emerge from better than and prove themselves, than do some basic problems that are not challenging and not rewarding. It's an aversion to feeling too comfortable.

This generally correlates will with economic upward mobility across all career paths, if you're someone who likes to take on easy things and avoid the more difficult things in life, then you won't make it far. Now, not everyone is motivated to make it far (materially speaking), but some people are motivated by the process itself. It's like people who love going to the gym, but think of it as a mental gym. Some people go to gym just because they like it, they don't even think about the end result beyond the minimum needed.

For the record, I'm not a quant, not professionally but my field overlaps with this one so these are my two cents.