Why was such a change made?
In its announcement, the company announced that this change was made to be compatible with the launch date of devices in the Google ecosystem, so that more devices can get the Android version early. Last year, Pixel 9 was introduced in August, but since Android 15 was not ready, it came out of the box with Android 14. With the new launch schedule, Pixel 10 will be able to come out of the box with Android 16.
In the new setup, Google will offer developers a major release in the second quarter and a minor SDK release adding minor features in the fourth quarter. This will require pushing forward compatibility testing, but the added benefit is that apps will have more reason to support these new features as more devices will be able to use them immediately.