>2 out of 5 people getting all the way to the end and discovering that research or teaching are not them living their best life sounds either very sad or pretty good depending on your perspective.

Research and teaching can take place outside of academia.

>A lot of people convince themselves that what they aren't feeling now will finally come to them after one more milestone, and as long as there enough milestones ahead of them they can play for time until it happens. Or they hit Sunk Cost and feel like they can't tap out now because they'll look like idiots, ignoring how much bigger an idiot you look like for wasting X more years of your youth and saddling yourself with even more debt. Or existential crisis with much the same outcomes. "Who am I even if I'm not..."

Learning can exist for the sake of learning and doesn't necessarily need to be reflected in career choice or identity.