There's been studies available for years that explained why 2-ch stereo setups are not as good as 3 or more speakers for creating more realistics soundstage, imaging, etc. The problem is that knowing something has more potential and meeting that potential are two different things.

I think the reason we all listen to 2-ch stereo still is twofold:
First we all have a whole bunch of music recorded in the 2-ch world, optimized for 2-channel playback. Fake processing on these recordings produces mixed results at best. Maybe it is possible to process these better, but I think most people just don't care to test every song or album out to verify this.

Second, there aren't enough good multi-channel recordings readily available that aren't still cost prohibitive in some manner. New formats require new equipment, and generally add price premiums to album releases.
And as was mentioned earlier, some surround recordings are doing the same thing stereo recordings did in their early going - showing off the surround capabilities without putting much thought into the overall execution of the album. It's great that drum beats can be pinpointed to 4 corners of the room, but how realistic is that?

Have patience though. The DVD has already revolutionized many things, and surround sound is definitely here to stay. It's just a matter of time until DVD-A, DualDisc, SACD, or some new format finally get widely accepted into the mainstream and we see audio finally take that next leap into surround sound.