I changed my phone this year only because I wanted Galileo support (for professional reasons). If it wasn't for that, I would have continued to use my three year old phone, which was already a two year old model when I bought it. Non IT folk typically don't need to change their phones unless stolen or broken - five year old smartphones have decent cameras and can use popular apps for social media, navigation, etc. Some still change their phones only so they can be seen with the latest gadget but most seem to have realised that this is a mug's game and that a flashy but inexpensive phone case can disguise the model and age of their mobile.
If I can't tell the difference between 720p and HD video on my phone's 5.5 inch display, do I really need 2K/4K resolution?