I suppose you could argue that Paul McCartney was middle-aged before he was middle-aged. Not only that, you could make a compelling case for him identifying with middle-aged, working-class masculinity of previous generations more fully that with that of his own generation. So many of his songs are nostalgic for an England that's "pre" something: pre-60s, pre-WWII, pre-WWI -- you name it.
The most interesting part about "We Can Work It Out" from this perspective is the way that Paul's stanzas are complemented by John's bridge, a test-run for "A Day in the Life" or the lyrical counterpoint in the chorus of "It's Getting Better All the Time." It may have been a "Paul song," but John's presence is very strong.
This gets me thinking about John's experiments with a melancholy confessional mode from 1964 onward. "Here I stand, head in hand," and all that.
Throw in George's Eastern self-help lyrics and you have rock as therapy to a degree that was, as far as I can tell, unprecedented.
I'd really enjoy a book about the intersection of rock and therapy in 60s bands. There's enough in the Byrds and the less-famous American psychedelic bands to bridge the Atlantic. Throw in the R.D. Laing-influenced therapeutic philosophy of The Who's Tommy and Mick Jagger's sneering denunciation of "Mother's Little Helper" and you have enough material for a rich study.
As you might imagine, both from what I've said here and what I've written elsewhere, I'm a lyrics man. Like my daughter, I've never been one of those people who tunes the words out. If the words aren't compelling, I have a hard time committing fully to a band. The intriguing aspect of the hypothetical book I just laid out is that it would permit insights into classic rock that would be hidden in music-centered approaches.
It's funny. I started out today trying to write an allegory and ended up with a book project. I suppose there's an allegory to be discerned in that trajectory too, but not one that I'm motivated to extract at the moment.