Should I be concerned about buying a Di2 only frameset? Ie the fact I couldn't retro fit a mechanic groupset if electronic groupsets don't take off, or if newer versions of electronic don't fit the existing internal cable routing?
I think Di2 is here to stay now.
The fact that we have Ultegra Di2 as well as Dura Ace along with Campy shows there is a market for trickle down tech.
yeah give it 4 years and di2 will be on Tiagra level. it aint going nowhere
Give it 5 years and some new must have fancy schmants tech that you don't need will come along and rob you of even more money.
One thing you can be sure of is that your mechanical groupsets will still be going strong long after Di2 has had it's day.