When the Samsung Galaxy S4 did not fare extremely well in 2013, the company decided to change things up a bit. Instead of just hinting at metal on the inside, they made the whole edge of their smartphone metal. Instead of just putting glass on the front of the device, they slapped glass on both sides.
In March of 2015, Samsung went premium style with their devices.
The Galaxy S6 sold OK, so Samsung refined the concept and the Galaxy S7 is selling well.
I would not suggest that Apple would be taking a page out of Samsung’s book, here. I don’t think that makes sense. Apple doesn’t really need to follow one company’s trends with overall smartphone release methodology.
If indeed they DO move back to a device with a glass back and glass front, they’ll find themselves back in iPhone 4 territory. Only this time, with a metal rim that’s rounded (if they do indeed stick with such a rim), they’ll find themselves compared to Samsung without a doubt.