Think of a fabricator as an OEM. iPhones are manufactured by Foxconn, and I'm sure their technicians contribute greatly to the manufacturing and design, but it's still the Apple logo that gets stuck on the back.
They certainly are art in this context.*
And I'd argue that Apple are one of the few tech companies that genuinely view their products as art objects, as well as being boxes of mass-produced consumer technology.
* There's a wider question about whether the mere act of displaying something in a gallery makes it art, but its one that many fine art postgrads haven't been able to get to the bottom of yet :)
Speaking very broadly: Designers manifest other people's ideas for money. Art is more when you bring your own ideas into the world because you want to.
so like it or not i would say that iphone is a piece of art that others loved and copied. (which is good and completely natural).
FWIW we're not taking about apprentices doing blocking-in, backgrounds, or minor characters.