Bass players are a unique type of musician. The function that a bass player serves is the root of any ensemble. The melody, harmony and rhythm of a musical piece are dependent on the bass for support. Without the bass part, the musical piece would be lacking a key element in defining the emotional content of the music.
Bass players know this, it is in their nature to know and understand this concept. That is what bassists bring to the music, an innate understanding of the how, why and what a piece of music is attempting to communicate.