They're not very useful computers in relative terms, beyond being very portable, and there is a lack of compelling new features in new phones.
Right now there is the spec grind which moves some people to upgrade, but most people won't see a benefit. I suspect phones are more important as a fashion accessory or status symbol at this point.
I upgraded our household as VoWifi is needed due to limited reception but I suspect thats a fairly small user case...
I spend a lot of time staring at photos from tons of different cameras. I pull in unprocessed raw and JPEG photos from DSLR and flagship phone reviews to verify that metadata extraction and raw image data gets decoded properly by PhotoStructure.
There is surprisingly little difference in image quality from, say, the OG Google Pixel to the pixel 2 and 3.
The difference between well-lit scenes at the same zoom on an iphone 8, X, and 11 is minimal.
If you show someone photos from a current flagship versus a 3-4 year old flagship, composition will matter (much) more than the hardware as to which is seen as the better image.
(Guh, didn't mean to come off as pompous! I was surprised when I realized this a while back and thought it would be interesting to share).
Anyway, you're correct: low-light photography is where there's been more recent progress, but it's mostly via computational imagery. Having a depth sensor for portrait shots has helped improve the simulated bokeh, as well.
My Google Pixel 1 takes fractionally worse nighttime shots as a current-gen pixel 4. They're both usable, but the pixel 4 is much faster at getting the shot.
Thanks for the insight.