And lots of people know the chorus of 'Yellow Submarine', but how many could sing a whole verse without a crib sheet?

I am reminded of an Alex Glasgow song "Geordie the Professional":

He sings "The Blaydon Races", (which he needed to rehearse)
But cannot quite remember if there is a second verse.


And that does seem to be the fate of many composed songs that become highly popular. The chorus may well be near universal (in some sizeable area), the verses all disappear. I bet you could read many of the verses as poetry without them being recognised. "Down at the Old Bull and Bush" verses, for example. A very few verses have greater recognitions for some reason, and I think "It's a long road the Tipperary" is in that category.