Better phones have better screen res ( IPS at 1080p or more for example ), better CPU ( Octa Core ), more RAM, quicker performance in games, better camera, water/shock resistant features ( extra features ), special charging features, and other unique stuff added on certain models ( like selfie phone ), try compare cheap Chinese/HK android phone in US $ 100-200 range to say, Samsung Galaxy S7 Edge that have VR accessories capability.
None of which directly impact the core features of a phone. That is the point I was getting at. The changes you mentioned would be like PS4 adding better WiFi, bigger hard drive, a nicer case, SSD, that sort of stuff. They improve the machine, but don't affect the core function directly.