Even though it remains unproductive, I think you've overlooked the main reason why this phenomenon occurs. Although greediness may play a large role in determining many of our situations, deplaning is done using the same procedure as "debussing" or "de-exiting-any-venue-with-aisle", right? So the prevailing rule isn't "be as greedy as possible", but rather "adhere to the most commonplace rule", which happens to be unusually ineffective due to difficulty in retrieving luggage.

The worst part about it is certainly that some people on the plane are actually in a rush. A simple announcement over the intercom to allow those trying to make connecting flights to exit first could ease the situation.