Well, just like everything else in life, there are many people who studies a subject matter but never become good at it. How many people in this world takes tennis lessons, swimming lessons, and not all made it to the Olympics! How many people learn the piano but can't even play a music piece decently.
For most, learning tennis, swimming, the piano etc are just hobbies. They think that they don't NEED it to make a living. But for a few who becomes really good at it, they not only loves it but made it their life.
Sadly, this is the approach we have towards the Dharma. For most, it is merely an intellectual exercise and it doesn't get past that because we simply think we don't NEED it but nice to know.