no original ideas vs. universal truths

I recently picked up the debut novel See You In the Cosmos by Jack Cheng. Intrigued by the book's similar premise to my work-in-progress, I was interested to see how the dead father and lonely brother would be handled.

I got more than I bargained for. A line in the novel is eerily similar to a line in one of my essays. "Echo of a Fall", published in Hippocampus Magazine in 2011, compares not having a father with being an astronaut:

“Don’t you miss having a father?” they would ask. I longed to say, Don’t you miss being an astronaut? And they would answer, I don’t know, I’ve never been an astronaut. And I would say, Exactly.

In Cheng's novel, the main character is asked by his friend Benji if he feels bad about not having a dad:

Do you feel bad about not having a dinosaur? Benji said he's not sure because he's never had one, and I said I feel the same way about a dad.

Astronauts and dinosaurs, both stand-ins for impossible things. Does this mean that, because we both landed on this idea, that it proves there are no original stories? Or does it show that both of us as writers have discovered the same universal truth?