You're mistaken. Yes, portrait mode on the 7+ was introduced in 10.1 on the 7+ rather than at launch. But this feature was never available on the 6. It requires the two cameras in the 7+ to create a depth map and then blur the distance. Nothing to do with autofocus. There's no feature that was removed other than the headphone jack.
Well IIRC the portrait mode was absent completely from the 7+ camera app.
This is analogous to the Tesla example, new hardware no software.
The fact that the 7+ has a different portrait mode doesn't matter, the app had none, and in this case the new Tesla comes with new hardware that provides a different and arguably better "autopilot" but the software would trail the release of the hardware.
Right but portrait mode didn't exist before iPhone 7+ iOS 10.1. They didn't take away anything and then give it back, they simply added that new feature after the iphone7+ was released. It wasn't just a standard optical focus feature that the iPhones had previously. It is using software to identify the subject and blur the background to give the effect of a dslr camera when shooting a portrait photo with a low aperature setting.
There were also another thing or 2 that came in 10.3 iirc.