He spent most of his time in bed? John Lennon did not write just one song, and he should not be under estimated.
So he's a couch apple instead of a potato.
I take each of his songs at face value. Imagine is NOT philosophically similar to Revolution or Why Don't We Do It In the Road?
Not at all. In the case of Revolution, Lennon was bouncing back and forth between pacifism and militant-worship. He's straddling that fence in an obvious way in the version Revolution 1 ("don't you know that you can count me out... in")
Why Don't We Do It In the Road is entirely McCartney, alone, even playing all the instruments. Nothing to do with Lennon, and one of those instances that proves that once they let their once-lofty personal standards slide, they were not immune to recording crap.
George Martin tried to get them to pare the White Album down to one good record instead of two erratic self-indulgent ones. And he was right. But they didn't.