I don't think the average consumer is thinking about junkware nor physical design, it's just most people have iPhones especially in tech / young adults and thus more want to be on iPhone to share messages, airdrop, airpod support etcetc. They've created a network effect.
> I don't think the average consumer is thinking about junkware nor physical design
Probably not, but a zero junkware/zero carrier meddling policy is a major contributor to the brand's premium image, which makes the whole lineup more desirable. The iPhone is an invariable, singular product no matter how it's obtained, even if it has different price points.
By contrast Samsung, etc undermine themselves by trying to squeeze out pennies anywhere they can. That's the behavior of a commodity, not a premium brand.