speaker don't care what music you play through them. The qualities that make for a speaker that plays classical well are exactly the same qualities that make it good for rock or folk music as well.
With all due respect to Ralph, who is both smarter and better looking than me, I don't agree with your assessment. I thought the same way, for years. But I firmly believe that it's hard, nee impossible, to find a speaker that excels at all musical genres. Not considering room and ears differences.
As I mentioned above, I feel that only an onmidirectional speaker can properly convey the sense of space and separation of instruments for large scale classical music, grand opera and large choral works. IMO the best speaker (I have heard) for this was a pair of Shahinian Hawks. But for jazz or rock - they are absolutely not my cup of tea. The Larsens are better and I think if I were limited to one desert island speaker it might be the Larsen 6. But I listen to a lot of classical music.
Right now I have a pair of Omega single drivers in my living room. Fabulous speakers; work with nearly every tube amp I throw at them. Although they don't so do deep bass (I mate them to a pair of subs) they sound fabulous for most of the non-classical music I listen to. They are also great for chamber and smaller classical ensembles but with large, complex music they just clog up a little.
Occasionally (mostly when the Mrs. isn't home for a few days) I schlep my Altec 19s out of storage. Also fabulous speakers, IMO the best horn speakers ever designed for home use. They are better than OK for large classical but not ideal. The notes are well separated but there is not the same sense of space and venue provided by a good omnidirectional speaker. Again, IMO.
You can come close using bidirectional speakers but not quite; although they can do some things better. I have to say that the best reproduced classical performances I have ever heard were played on (3) Magnepan 20.1 speakers and a Meridian 568 processor using Meridian's Trifield 3-channel mode. It was the closest playback experience to a live performance I have ever experiences. The Downside - requires huge speakers in a huge room. But if I had Ralph's money... I would burn mine. ;-)