I agree with this.
I bought an iphone 12 this year because my iphone 6s+ is 5 years old at this point, and I wanted to spoil myself. My new phone feels basically identical to my old phone, and despite 5 years of innovation I think it was a waste of money. Most of the improvements in iphones in the last 5 years has been in software, and the 6s (for now) still gets all the updates anyway.
There's some differences - low light photography is much better. My new phone is also physically smaller with the same screen size and much snappier. But its also missing a headphone jack, force touch and it can't be unlocked with a face mask.
I think next time I'll keep my phone until it dies - which I'm hoping will be ~6-7 years. Given that sort of longevity, the price seems pretty reasonable.