With a musical output up until Let it be that is the same as OTL, how can we extend the Fab Four's career into the 1980s or beyond? What great music they might have written in the 1970s? Pick any POD and give it any date, but keep their music the same up until after Let it be and/or Abbey Road. Might we see Imagine, Band on the Run, It Don't Come Easy or My Sweet Lord as band efforts?
Four points come to mind...
1) Management
You'd need to sort out the management vacuum left by Brian Epstein's death - FAST. I doubt that Brian would have been able to keep them together if he'd lived (possibly too biased/smitten towards John).
I dunno who'd be a good candidate for that - but they need to be in place by the end of 1967 to avoid the whole Apple fiasco.
Whoever gets this job needs to have a strong will, but be fair and inpartial for ALL the Beatles. Tall order.. and I struggle to think of who could do this. (lots of egos involved here)
2) Songwriting volumes
How to deal with the mass of songs being written - With John and Paul churning out tons of ideas in 1968-9, and George becoming more and more prolific, how can one band keep up with all that creativity? Does this require a series of double-albums? More frequent single albums? Side-projects? (Hey, maybe a Paul/Ringo album..?)
3) Live performances
After they retired from touring the technology continued to improve - amplification, security, lighting.. not to mention the audiences actually starting to LISTEN rather than just scream. How would a live show by the Beatles in 1968 look? Would it still be stripped back to just the 4 of them.. or would they get hired hands & friends to embelish the live sound? Bands like the Mothers of Invention and Chicago were going down this path, so it's not totally out of the question.
4) Yoko
I saved this to last, because even with Yoko out of the picture, any of the other points above are still tough questions.
Still - how to accomodate John's partnership with Yoko alongside membership in the Beatles? (Hmm.. perhaps setting out a calendar with time assigned for solo & Beatles projects)
I refer to point 1. Strong, impartial management is needed. Any takers?