I think that we humans are simply unready to know what we want to do with our life by the time that choice arrives and the fact our society reinforces and pushes the idea of having every choice be available constantly makes us uncertain and rather lost in our path to find what we want to do. Most people struggle to even decipher who they want to be, let alone what they want to even do. So, I think people should have some choices actually outlined and enlightened in a way for them to focus and work towards instead of giving every single option known to man in our current system. I kind of got lucky by knowing who I was(kind of by the end of middle school) and what I wanted to do pretty fast(by the end of highschool) . But, I highly doubt majority my colleagues are even certain of their decision of their university or major let alone what career or things they want to do in life not have it be literally outright decided at birth, but by simply observing what their parents are like and into as well as what they are like as an infant and early childhood. To give them an idea of what they could be and suggest the idea of what that could actually be in a range of choices in a subset of everything rather.
Although obviously there will be outliers who aren't like anything like their parents or their childhood. Who would do clearly well to do something completely unrelated to both of those factors, but I think a large majority are generally like their parents and early childhood environment and reaction to it.