Why not call it Godzilla vs. Anguirus?

I know the fight is over half way into the movie, but I like that title better. The other titles are pretty lame. I'm partial to the Gigantis the Fire Monster title, b/c as a kid I thought the title was named after Godzilla's opponent until I actually watched it.

We’re trying to pretend as if these comic books don’t exist. - David Goyer on the DCEU