Max Horkheimer once said that the division between theory and practice is because academics are alienated from the product of their own labour and I think about this all the time

or as bell hooks put it,

"Just as some elite academics who construct theories of 'blackness' in ways that make it a critical terrain which only the chosen few can enter -- using theoretical work on race to assert their authority over black experience, denying democratic access to the process of theory making -- threaten collective black liberation struggle, so do those among us who react to this by promoting anti-intellectualism by declaring all theory as worthless. By reinforcing the idea that there is a split between theory and practice or by creating such a split, both groups deny the power of liberatory education for critical consciousness, thereby perpetuating conditions that reinforce our collective exploitation and repression."

• from bell hooks, "Theory as Liberatory Practice"