Young people are ambitious and believe the odds don't apply. Academia is no different than other highly variable status-seeking paths, such as entrepreneurship or sports. Different personal values, same basic combination of youthful idealism and hubris.

The west would atrophy and die if everyone took the path of least resistance to a comfortable lifestyle. Market economies with perfectly rational actors would cannibalize themselves in a single generation.

However small the number, some people believe that the correct direction isn't copying others' path to success.

Between the sunk-cost fallacy, and how many years both grad students and would-be grad students have spent on the ivory tower's propaganda treadmill, with little other (adult) life experience to be able to objectively judge things...