Okay . . . it's already been threadjacked into a Di2 thread. But just yesterday I seriously considered having a cable actuated bike as my primary bike for the first time in 8 years. The thought didn't last long. Most of the reasons I wouldn't consider a non-Di2 primary bike have already been listed above. Add to those the fact that you can't use a remote/climbing shifter in a cable actuated system. And that, once adjusted, unless you change components, you never ever have to adjust your derailleurs again. (Di2 cables don't stretch.)
But the biggest one for me? I hated how shift quality diminished over time with cable shifters. And this led to lubing/replacing shift cables (and bar tape) every six months (sometimes a year). Di2 is set and forget. Got no barrel adjusters. Needs no barrel adjusters. It's a beautiful thing.