Xiong, I for one don't see any inherent difference in literary value between written fiction, filmed fiction, illustrated fiction, audio fiction, or animated fiction.
Its true that TV anime usually does not have intelligent topics or have much to say about ie. the human condition. But I don't see this as being any different from the general lack of academic topics in American TV drama (The Hills, Heroes, Sex and the City, etc). Compare any kind of TV show (animated or live-action, from any culture) with what is achieved in film, there is a huge gap. TV always prioritizes the entertainment value, in film there is freedom to do anything.
In terms of what can be achieved between written language (novels) and moving Japanese illustrations (anime), I believe they have the same potential for excellence.