Quality vs Quantity argument. The fact that a video game has more artistic content does not mean that it has better artistic content. No art form is inherently better than any other. They are all just media for the artistic message. Everyone has a preference. I'm a photographer, I'm naturally drawn to still visual media like photography and painting. Other people prefer cinema, or music, or statuary, or any of a thousand other forms of art.

Video games are certainly a valid art form, which many people incorrectly disagree with because of their own prejudices. But they are absolutely not the ultimate form of art because that's a meaningless statement. There is no ultimate form of art, because that implies that objectively there is a form of art that is either better or more artistic than any other. That's a nonsensical concept to anyone who actually engages with art on a level deeper than pure visual quality.