I could also imagine that a Boeing pilot generally has more respect of the machine (s)he's operating because of the direct control. The overall deadly accident rate in Boeing vs. Airbus, plotted over time, would be interesting.
Both aircraft are so incredibly safe with vanishingly low accident rates, that it'd be nearly impossible to suss out accidents due to the respective designs versus pilot error, weather, carrier procedures etc.
The silly thing is they could combine the fly-by-wire system with the boeing-style control system if they wanted to. There's no reason why not, other than the space in the cockpit I suppose. It's basically just a much bigger joystick, no?