I think you're sort of on the right track, but I think it has even LESS to do with potential technological or engineering innovation.
My sense is that the finance people have basically taken over, and that technology/engineering is being completely driven by financial modeling. Basic technology and innovation is being dictated by what the elaborate revenue models tell them, and the models are built in a way to min/max production cost and consumer spending.
I see this in all kinds of technology situations, where what appear to be the dumbest engineering decisions are made because it requires you to spend more.
I expect the same with the elimination of the heapdhone jack. They will eliminate the 3.5mm jack and replace it with a lightning based audio connector. The specs won't be released until after the phone is available to purchase and they will be the exclusive provider of native Lightning headphones *and* Lightning-3.5mm stereo adapters at huge premiums, raking in nearly exclusive revenue on them for months. They will eventually acquiesce and approve third party 3.5mm adapters, but their licensing process will also also guarantee they get a percentage of ALL of them.
Now, if you look at it from a technology perspective, maybe the 3.5mm jack does need to go. But you don't need much of an imagination to think that maybe there could have been some other jack design implemented that would have still have accomplished the other putative design reasons (thinner, more internal space) and not tied up in a bunch of exclusive-to-Apple IP.