Mono was a great idea and, in many ways, a lot better than stereo.
Everything we hear in the real world comes from a mono source. A violin is mono, a person singing is mono. All are single sources. A mono reproducing device gets closer to replicating a single point source than anything else.
What’s missing from mono, of course, is dimensionality and spatial/directional cues. Alan Blumlein (widely credited with inventing stereophonic sound) borrowed from stereoscopic viewers to create a phantom image between two loudspeakers that gave someone standing in the middle directional and spatial cues.
What’s missing from stereo, of course, is a convincing illusion available anywhere in the room.
Just as you need 3D glasses to appreciate the illusion of a third dimension, hifi listeners are stuck with a small fixed window to appreciate the phantom image of stereo.
We can do better with less.