Kubrick wanted above all, irony. And so he used the Blue Danube in "2001," the piece you mentioned Guy, the Mickey Mouse Club theme song in Full Metal Jacket, Beethoven's Ninth Ode to Joy at the end of "Clockwork Orange." Kubrick was a complete artist of the most severe, uncompromising kind imaginable, and so he used whatever he could to get the effect he wanted.
So obviously he was going for something that cut away all conventions - unless those convetions helped what he was trying to do. Having a complete, well-organized score - like Alex North provided - meant nothing to him unless it gave him the effect he wanted.
However, despite the fact I am acutely aware of Kubrick's ironic and unconventional approach in "2001" (I saw it forty times when it was first out in the theater) I still think the score North did may in fact have provided what Kubrick wanted just as well as the temp track which is what he used.
So obviously he was going for something that cut away all conventions - unless those convetions helped what he was trying to do. Having a complete, well-organized score - like Alex North provided - meant nothing to him unless it gave him the effect he wanted.
However, despite the fact I am acutely aware of Kubrick's ironic and unconventional approach in "2001" (I saw it forty times when it was first out in the theater) I still think the score North did may in fact have provided what Kubrick wanted just as well as the temp track which is what he used.