Donīt know much about the 737īs and the A320 series from the flightdeck. But there is no question that Airbus are lightyears ahead of Boeing when it comes to where the plane cost money, and thats on the ground. Even if the B737-6/7/800 have slideing carpet it will still take about 20-30 minutes to unload luggage, cargo, and mail on a fully loaded 737. And then it needs to be loaded again. And normally it wil take atleast 4 workers to do the job.
The Airbus can be loaded and unloaded by two workers, because of the container system. If the outgoing payload is at the apron, the turnaround can be done in aprox. 15 min.
We once had a LH A321 that came in 30 min late. We unloaded, and then loaded in 12 minutes, waited for the fueltruck to finish, pax in and out, and they left on time.
Just my oppinion