Like the brands I've mentioned, Apple buys their camera sensors (from Sony), battery, and display. And yet they don't have the best camera sensors, the newer higher capacity batteries, the latest display tech, etc.
You can go 2 or 3 iterations before seeing a real improvement, and it's not always because better tech doesn't exist. They're just not pushing hard.
Apple Silicon in the past 5 years has trounced every single market player. Apple has to make decisions on things like sensors based on the supplier being able to deliver hundreds of millions annually -- by the time we see the hardware it was baked and locked in over 12 months ago.
Apple introduced 48MP camera sensors many years after they became available. For the past 2 or 3 years, there have been devices with much better cameras, but again, they're not iPhones. Some phones have been charging at peak 40-100W for a while, so when you look at Apple's 30-40W, it's not that impressive, is it? In a year or so they may release a foldable phone, but Samsung is already on the 7th iteration of the Fold. And so on.
It doesn't make their SoCs less impressive (typing this on a M4 Mac!) or the shipping of so many devices a lesser feat, but Apple is very conservative with iPhones, and that's very apparent when you look at all phones out there.