Europe

Phones haven't been thin since manufacturers started to stick half an inch of lens of two or more too many cameras on the back. With some clever engineering, phones wouldn't have to get that much thicker. They could just smooth off the back and shuffle the components.

They wouldn't need cases so much if they were (a) made properly and (b) made repairable, either, but that's another uphill battle.

While I'm moaning, can I also complain about shitty glass screen protectors that add another couple of mil to the thickness and break constantly. Never had a screen crack while using a thinner plastic screen cover but they're almost impossible to find nowadays.