Yes, very well put. John often liked to overstate or misstate something in an interview, just to make his point. So his statements, while colorful, do not necessarily reflect more than his mood of the moment.
Absolutely. John was also a natural iconoclast who liked upending people's assumptions about himself, The Beatles, and everything else. Remember this from "And Your Bird Can Sing?"You say you've seen the seven wonders
And your bird is green
But you can't see me
you can't see me
That's John. He's probably talking about an affair he had or something like that, but those last two lines are a self description, and how he liked it, I think: You don't get me.
A lot of his post-Beatles declarations are also those of a man trying to separate himself from his own past and from a media-created image he had come to detest. The end of his marriage to Cynthia just might be an overlooked factor here as well, although of course by no means the whole story: it's startling how little she is mentioned (if at all) in his seventies interviews. You get the feeling that from about 1968 onward (the year his marriage broke up), John really wanted to recreate himself, personally and professionally, with the past firmly relegated to the status of unsatisfactory prologue. It's all John-and-Yoko, here and now; don't talk to me about Paul, Cynthia, or The Beatles. He's by no means the first person who's tried to do this, but he's one of the few who's had to try to pull it off in the full glare of the media with all of them wanting to know when he was going to go back to the very past (The Beatles) he was trying to rid himself of. Put that way, maybe it's not surprising how stark some of his statements were.