I don’t think anybody really cares about an extra half millimetre of thickness, especially if it means that you can save hundreds in replacement costs and extend its life by a few years. Nobody’s buying an iPhone and busting out the calipers to compare it to their previous phone.
Apple’s sales fall and people don’t buy new phones because “it looks just like last year’s phone.”
There are so many things a company can change about a phone besides its thickness.
You also start running into usability issues. There’s only so thin a phone can be before it’s less of a phone, and more of a blade that’ll bend if you sneeze at it wrong.
Happened with the iPhone 6
I care. This thing’s already thick and heavy enough, and I don’t particularly care about popping the back off my phone to replace a battery. It’s like…once every two years that I have to replace it.