Material choice for premium look and feel, ie glass and polished metals. These things look and feel premium, justifying Apple's premium pricing. People also like those look and feel, with majority of Android OEMs copying what Apple is doing in terms of design and material choice.
I miss the days of heavily textured surfaces, like the rubbery plastic of the original Moto X/G phones, or the highly textured design used on the 64GB OnePlus One. Those were a delight to hold and provided excellent grip. But the general consumers have spoken, and they prefer shiny smooth look and feel.
Houses in SE Asia, most of us have marble/marble like tiles for our floors, which are smooth, shiny and slippery. One would think it's a hazard, especially with the elderlies, but nope, people prefer those shiny look, even if it can cost them their lives. 😂