Historical meaning is pretty worthless though. It's like saying CPU's are going backwards because the 386 was a bigger jump. Technology matures eventually and that's not a bad thing.

Android doesn't really work on hardware changes as AOSP doesn't run on a single phone on earth anyways, not even the emulators, this is the goal of the manufacturers.

For the features you can read here for example what Android 16 changed:

https://www.android.com/articles/android-16-features/