Bob is not wrong. (at least not about chainline per se).

Way back in this thread I pointed out that continually widening the rear end would come into conflict with Q-factor concerns, and that's exactly what's happened. Moving the cassette inboard 2.5mm back to the 130mm chainline helps, but it totally negates the reason for going to 135mm in the first place. Moving the crank out to meet the chainline messes with the Q-factor. Leaving it alone, combined with narrow chainring spacing can cause outer ring rub, when riding crossed to the inner ring (what I call shadowing)

This isn't a matter of right or wrong, but of choices and priorities. You can't have it all ways, so need to decide what you want and what you'll give up to have it. It seems that many have come to accept the shadowing issue as par for the course and are willing to live with it. For my part, I prefer not to, but don't like the kludge of moving the cassette inboard. So I'll stay with 130mm for the foreseeable future, but then again, I don't want disc on the road anyway.

to Bob -- I think that producing an inboard cassette hub like you propose would be a marketing challenge because folks have already come to accept the shadowing problem. It's a kludge solution that really says we should go back to 130mm, disc or not. Of course, if you can convince an OEM of the logic, that would change everything.