I'd say that's correct...
People around the world have driven Land rovers everywhere for decades with open diffs front and rear!!!!
The ability to drive a clean line, good throttle and brake control, correct tyre pressures and an eye for the terrain will get you a very, very long way :D
TR assists further, and with articulation limits of some modern designs further improves this...
After all, motion is a simple equation.
Traction + torque = motion...
(very simplistic)

