If as commander in chief, one has to be saved by other warriors from getting killed, one is a liability to the army. Dhrishtadyumna usually got the worst of it from Drona, Ashwatthama, Kripa and Karna, and always had to be saved by either Satyaki or Bhima.
Given the overwhelming superiority of the Kaurava army - Bheeshma/Karna, Drona, Kripa, Ashwatthama, Bhurishrava, Kritavarma, Shalya, Vrishasena, Bhagadatta, Shrutayudha,... it was important for the Pandavas to optimize their resources so that each could be properly engaged. That was tough to do if somebody always had to salvage their senapati from getting killed
As in Drona needing rescuing at least once that I remember? As in Satyaki going after Arjuna/Krishna to help them? The last one was during Jayadrath vadh. As in the entire Kaurava contingent being kept occupied by Abhimanyu instead of capturing Yudhishtira as they originally planned?
(I didn't make as many notes on war parvas so don't have citations at the tips of my fingers, or I'd have posted)
The only two people I don't recall needing help OR running from the enemy are Bheema and Bheeshma.