Stereo means "solid", and in stereophonics, the ability for two point sources to use phase and intensity to generate a consistent audio sense of solid sound sources in depth as well as width (an image). Most stereo sources (LP, CD, Stream) are able to create this effect. There is no other reason to have speakers laid out left and right of the listening position.
Bose 901s are not designed to recreate this image. They do not reproduce a set of solid sound sources in depth and width as the recording engineer intended. They are fun and initially impressive, but they do not reproduce an image with high fidelity.