Talk about leaving us hanging:

'Grandpa!' I shouted. 'Be careful! Oh, gee!
Who's going to drop it?
Will you...? Or will he...?'
'Be patient,' said Grandpa. 'We'll see.
We will see..." (200-205)

"We will see"? Seriously, Seuss?

The Doctor makes it clear that neither Grandpa nor VanItch are willing to back down and show weakness in the face of their adversary, even though they're both are well aware of the consequences of their potential actions. So—what happens?

That's where we come in. Because of the cliffhanger, we are called to resolve in our minds that which the Yooks and Zooks cannot. That final, empty page that faces the image of Grandpa and VanItch invites, and even forces us, to fill-in-the-blank. Dr. Seuss is most definitely not giving us a solution.

Maybe Seuss wants us to resolve not the story, the real world issues that the story represents. Adversarial global and local environments? Xenophobia and close-mindedness? They're big things to battle, but hopefully we're up to the challenge.