Both situations benefit from the efficiency of modern production lines, but in the former case that device can be easily refreshed by a lay person out in the real world while with the other phone, the same amount of manufacturing resources went in to a phone that only lasts two years.

No matter how “efficient” our modern manufacturing methods are, using them to make a device that lasts two years uses more resources per unit of delivered utility than using them to make something that lasts 5-10 years.

Also the reason why it’s cheaper to manufacture new than to repair is exactly because repair is not engineered in to the design. If you have to de solder a battery and crack a case to replace a LiPo, it’s going to be more costly than if you just remove some screws and pop out a connector.