Watching Get Back, we hear John complain about there being too many chords in George's songs.
Could it be that John didn't play due to insecurity?
George was the best guitarist in the group, and knew and enjoyed far more chords than John. If George brings in a song, John is left n the position where he has to learn what George has already written in order to play the part:
So
- John can't find his own groove - and that's what he does
John can't play the part as well as the junior partner in the group - and this will be on a recording for the world to hear
If this is what's going on, it puts the cases where John is 'thrown a bone' with a solo here or there in Get Back in a different light to the general consensus.
It's not necessarily a case of John being given some spotlight to draw him out of a drug haze and become interested.
It might be his mates generously giving him something with a bit of cool factor so that he feels less inadequate in front of the cameras. A confidence boost.
George even supplied a basic 12 bar blues song that was super easy to play so John could play slide.
We have to remember that at that time, not only was he self medicating, but the reason he was doing it can't have been unrelated to Yoko's miscarriage about 6 weeks before the Get Back sessions started.
He needed the odd win.