Stairway to heaven is a song about a lady who is trying to find happiness through accumulating wealth. It is primarily about materialism and greed. The lady and her stairway represent materialism. It is about how selfish ambitions cut us off from other people and God. The need for materialism is about approval to some extent.
As time passes on, our material selves are now more important than our spiritual selves. A close inspection of the entire song demonstrates a consistent difference between things seen and things heard. Things seen are often through fallacies and misleading deception. In contrast, things heard are usually real and from the heart.