Earlier quoted context omitted.
No, you missed the point. Speeding up deplaning won’t help much because of all of the things happening below the passenger deck (unloading baggage, unloading packages, emptying sewage, etc.) and in the cockpit (debrief). Getting passengers off quickly won’t help speed up the general post-flight process much. It’s very rare that the bottleneck is waiting for the cabin to be cleaned.
Some of the deplaners hold up the next flight they need to board. Airlines could optimize that.
Also, the US airlines will not hold a flight due to a delayed inbound unless it’s got a shitload of the passengers. I’ve seen Delta depart on time and cause 10 passengers on a delayed flight to miss by only 15 minutes.