End of an era
The end of the dock looks like a materialization of the end of the "digital hub" model. The Mac was the spaceship and the portable music player would connect to it through a
pod bay, like in 2001.
For me, the dock was really materializing this "pod" part of the name iPod. I'm French and Pod sounds like "Pied" (foot) - like in the word "pedometer". The dock really was the foot, a necessary support piece and umbilical cord for the device to stand and connect to its mothership, the Mac.
But now Apple has shifted to a new paradigm. You don't need to connect your iOS device to a computer anymore, even upon first use. It is cable and tangle-free with Airplay, Airplay mirroring, Airprint, iCloud, iTunes in the cloud. So it sounds normal to let the dock go now. It is too much of a symbol of the Old Days !