The Iron Giant was a beautifully done satire on the paranoia of 50s America and the Red Scare, and actively promoted a pacifist ideology. The titular character even says, "I am not a gun".

In Ready Player One, the Iron Giant is turned into a gun. And nothing more.

Ready Player One doesn't care what art has to say, it only cares what art looks like. It appropriates the art of others into a self-insert fan fiction that doesn't understand theme, subtext, or anything substantial about what film and games actually are.

It is one of the first films I've ever seen that I would have a hard time actually calling 'art'.