Kubrick once said he refused to explain what 2001 was about because it would be like knowing why the Mona Lisa has that particular smile. I shackles you to one particular perspective (the filmmaker's) and stops you from drawing your own conclusions or having your own experience.
And some of the theories I've read about what 2001 are about are pretty fascinating, even if they're not what Kubrick intended.
As for myself, I was watching the film for maybe the third time back in the late 80s and something hit me about the intertitles that changed the way I viewed the film's narrative.
There are three title cards in the film:
- The Dawn of Man
- Jupiter Mission Eighteen Months Later
- Jupiter and Beyond the Infinite
But there's no title card for the four million year jump cut from the bone to the satellite bomb. I thought this curious, then paid attention to what was happening in the australopithicus and Dr. Floyd scenes. Lots of shots of "people" eating, living drab, listless lives. And then it hit me that when we're with Dr. Floyd we're still
in the Dawn of Man. The tools have become more sophisticated (bone club=bomb), but we're still those same apes. The jump cut is only a transition in TIME, but we're still in the same scene. Nothing has really changed. We have mastered tools but we haven't yet really transformed. We're still tribal (ape tribes fight over water hole, Americans and Russians in conflict).
Seen in that light, the Discovery scenes still portray the humans as this lifeless dull species, but now man's tools have outlived their usefulness. Unplugging HAL is perhaps symbolic of leaving the tools behind. That the Discovery has a silhouette that suggests that bone club is surely not a coincidence. Bowman leaves HAL and the Discovery to make that trip in which he ages, dies, and is reborn as something new, and he returns to Earth naked with neither clothing nor tools.
I'm not saying this IS what was intended, but it's one way of looking at it.