[kelnos]

It sounds like you've decided that "luxury good" means "anything that's more expensive than a competing product by an arbitrary dollar amount I've decided on".

That's not how the concept of luxury goods works.

Also consider that Android is not a 1:1 replacement for an iPhone in the same way that a Honda is a replacement for a Mercedes-Benz. Lock-in and ecosystem interop matters a lot more for a phone than for a car.

I would probably buy into the idea that a Pixel (for example) is a luxury Android device, but not that an iPhone is a luxury smartphone in general.

[Dalewyn]

Luxury good is anything that is not strictly necessary for a given purpose, in this case daily life. You will likely need a smartphone of some kind in this day and age to live, but you do not strictly need an iPhone. Hence, iPhones are a luxury good.