But in this case for feature after feature the reason it makes the devices much more similar was that at that stage the iPhone UI decisions made obvious sense. There's a lot of stuff along the order of "we've tucked stuff off in the border somewhere in a color that blends in, but we need to make it bright and put it in a noticeable position" where the iPhone was a good example of UI done right but where the same overall direction could be had by looking at any number of other products (and not just phones either).

I've not read the whole thing, but I've not seen any clear examples where they've had lots of choice in how to make things better without making things more similar to the iPhone. Now that's an impressive testament to the quality of Apple's UI design, but most of it is "obvious" - the problem isn't that it's hard to figure out that you'd like a "previous" button to go with a "next" button, but that it takes a lot of attention to detail to get this level of consistent quality throughout the product.

And Apple does that well, and Samsung at that stage clearly had not done all that great.

If Samsung had put in that attention to detail, the devices would likely have been a lot more similar from the outset.