I just thought of another good reason for the campy triple that doesn't have to do with performance, but durability!
Since both conversion cassettes ($65+) and 10 speed chains ($50) are so expensive compared to the regular shimano stuff wouldn't running a triple be better for chain wear (and subsequently cassette wear). The triple would be much better at maintaining a straight chain line. THe are enough gears that overlap that I shouldn't ever have to run a combo that produces a lot of chain deflection.
I think reduced maintenance costs with proper gear selection the triple is probaly the best reason to use it rather than a double.
Am I full of **** or does this sound feasible in real life? I would hate to spend $115 for my chain and cassette if I wasn't getting a lot of mileage out of them (at least relative to a double)
IMO, proper care and feeding (lube etc.) of the chain will have more to do with extending the life of the chain than using a triple. In actual fact, but of little consequence, a double will have a better chain line than a triple, less angle of departure from the chainring across the cogset.
All that said, 10 speed stuff is horribly expensive with little gained.
Of course you are correct in an absolute sense, but in a practical sense, well it doesn't make any. To do what you want, maintain a straight chainline with your triple, you would be changing gears much more frequently. With more frequent gear changes come all the assorted wear and tear on cables, shifters and the rest of the drive-train. And that's assuming perfect shifts are made at all times. I'm a triple user, lord knows I need the gears I can get in the hills that surround me, so I'm not an anti-triple guy. It seems to me to be an awful lot of work playing with your gear selection to, hopefully, save on maintenece issues.