Huh, I've always found deplaning fast except in the case of the person who's overhead is three rows back. There are ways to make it all faster but require some systemic changes to how we travel.
Now a-days a lot of travelers will try and cram their entire luggage into a single wheely bag that they struggle to lift into the overhead bin.
Ryanair does that now.
I started to pay more attention, and am 100% sure at least between AA and SW, it literally takes AA 4-5x longer at the same airport vs SW.
I've only been failed by them once, and they gave me a hundred bucks for the hassle ($50 per bag). Not a bad setup.