Yes....See your point about horses for courses, etc.....and why a 777 looks a bit different from my old t/p's.....
Just that it's always struck me that given aerodynamic law is more or less inflexible, then aircraft have to be designed within these parameters - so if Boeing and Airbus are both designing / marketing / building generic aircraft for a certain market but not for specific customers or to customers' specific specification, then why wouldn't the 777 and A330 or the 787 and A350 ( more or less same range. size, possibly engines ) look and be more or less identical ?
In particular, I was thinking about wing profile / sweep / area / location ( which provides all the lift ) when depending on the various models, the airframes are more or less the same size, all are twins, all have more or less the same flight envelope/mach requirements, etc....
Still have a hunch that there's a little bit of ' design branding ' goes into the final product - think cars, motor yachts, etc, all fairly easily identifiable to specific manufacturers....
No big thing, as I said, it's just that I have always been curious....
And, back to the original post, maybe it's just that winglets were not en vogue when the 757/767 were originally designed, even if the technology was already known and available....