Students are classic bourgeoisie - often from well off families and tend to be pretty comfortable and not preoccupied by their next meal. Most student uprisings are derided for being so privileged but such is always the way. They say the 1968 French student movement was diffused because they left Paris to spend national holidays at their parent's holiday homes :)
They are also indicative of two other key predictive factors: elite over production and a demographic youth bulge.
Their lack of success is perhaps the power issue. If they waited a few years to become army officers, administrators, judiciary and such they could be much more successful than doing another sit-in!
The two notable rebellions in the US were by land / slave owners. Students are limited to basically SDS / The Weather Underground that didn't go very far.
> You find professionals like lawyers leading revolutionary movements, not farm hands
Yes, but also students (who have the time and education, but not money nor power).