Its safe to say, at this point, Apple is playing musical chairs with the iPhone hardware.
Lets recap:
2007 - multitouch, all screen phone, Internet in your pocket
2008 - 3G
2009 - video recording
2010 - Retina, Facetime
2011 - Siri
2012 - bigger screen, 4G/LTE
2013 - A7 64 bit
2014 - 4.7, 5.5
2015 - Force touch, 4K video recording
2016 - computational photography
2017 - truly all screen, OLED, A11 Bionic, Face ID, Animoji
2018 - now this is where it starts to get muddy - what was the standout in XS and XR again? bigger scree, 6.5 I believe.
2019 - Three cameras, more computational photography, I must admit, I did see a dramatic improvement in the photos.
2020 - 5G
2021 - Blurring people when recording a movie
2022 - Always on display, Emergency services, Photonic engine (which some are debating make photos worse, dynamic island.
2023 - thinner bezel