Yes, you’re right, I didn’t think about it, but now that you tell me, I realise that if one highly unrestrained artist makes a restrained appearance once, he is in fact a restrained artist. Good point.
My own personal theory about British rock completely agrees. Also, some of the British rock bands grew up during the Blitz and 1950’s Britain suffered economic troubles. That is a breeding ground for art. Look at the post WWI era (Fitzgerald, Parker etc.)
Please. His whole career was restrained, mostly by Col. Tom. See any of his movies.
Even if you want to limit his career to the few years before he went into the Army, I’d argue that he was deliberately restrained in order to appear tamer and be more acceptable in almost all his television performances and many of his live appearances. Compared to black artists appearing before black audiences, he was a model of decorum.
You can try to make an opposing case, and I’d like to hear it. I’m just very doubtful you can given the realities of 50s rock & roll.