Earlier in the panel, it was mentioned that at an early Comic-Con the show attended, Stephen Amell had noted “if we do this right, we could run for 10 years.”
Ultimately, the show decided to cut out a little early, and producer Marc Guggenheim mentioned that cost logistics and wanting to go out while the show was still popular, “while people were watching the show,” were factors as to why the series won’t ultimately make it to Season 10, as well.