They decided it years ago, and its rational to allow time for manufacturers to adjust vs them immediately being barred from selling freshly made devices.

Users generally welcomed this as we can get away from proprietary connections and chargers for devices to a standard that always works when you plug it in. Apple, and by extension some fanatics, opposed it because they'd lose rediculous gravy from not being able to license and sell lightning cables, and the next new proprietary cable and adapter.

In short, fuck Apple.