I agree Jason Lee did a great job. Which is funny, because I think he's a terrible actor in live-action films. The same thing with my reaction to Albert Brooks' work in Finding Nemo. I guess their live-action acting seems too forced to me. "Acty" acting. But you need a bit of that...
And I believe that's all he was saying. I don't think he personally thought at any time there was nothing to be learned from classic animation. He was just phrasing it that way to derail the "2D is dead" mindset present in some of the audience.