All good points RiddleOfSteel. I've had to update my 8 speed Campagnolo Record gruppo to 10 speed when replacement parts went from expensive to quite hard to find, and now watch the same process happening to the 10 speed parts, so learning a lesson I am buying back up supplies for the decades ahead.
On the Di2 I have a different take. To me cable shifting has reached a pinnacle and is nearly bomb proof, while electronic shifting adds several issues.
Switches and mechanisms, when you push a button you are activating a switch, which in turn must activate some mechanism to move the front/rear derailleurs. Electronics fail and are not roadside fixable like a broken cable or a derailleur where simple tools and a spare cable will suffice (and yes some carry these particularly on long tours).
Then there is the support question, the million dollar exotic cars of today face this issue just as the electronic shifters will, where will you get the parts to keep the electronics, as they wear out/fail. working? Then if there is code involved/chip sets to run the shifter will the manufacturers treat their product like your last cell phone, as a throw away product? This is the greatest virtue of vintage bikes they come from an era where you threw away nothing and instead just fixed it (I have a 30 year old 800watt Kenmore mixer built the same way and have the entire back up parts for the gear drive and electric motor rebuild-as long as there's electricity this will work).
Finally the issue of batteries and weight, can you really trust a battery on a longer ride, or, as do most who need their electronic gizmo to work, will you carry a back up battery or cordless battery charger so in the event of a battery failure/drain you can still make your electronic device work. And batteries are still extra weight, a lot more than a spare coil of shifter cable.
These complexities inherent in the electronic shifters will keep me home with brifters or barcons and cable until I see them bettered. Perhaps in a race bike they make sense where the support and back up is no issue, but for now I'm happy with cables, though no luddite I love our 200mm cable disc brakes on our tandem.
Last edited by since6; 04-08-18 at 07:41 AM.