Are you considering a phantom center in your statement, or referring to something with more sweet spot spatial definition?But, haven’t you heard? We only have two ears. So, we only need two speakers.
Now, that statement has been said by many out on the Internet. If only it were true! I’ve had many speaker brands / models in my lifetime and could never get a three-dimensional soundstage with any of them. They’ve all sounded flat and two-dimensional. The exception is tall panels like electrostatic and magneplanar type speakers, which come close. Today, I can get a proper three-dimensional with stereo using Auromatic (Barco Auro-3D).
To be fair, I've heard things (in stereo) from my speakers that sound like it's coming from a non two-dimensional spot.