How can Wilson Audio speakers sound that good if they are using OEM drivers?

fsonicsmith,
There are worthy exceptions, Vivid for one.

I don't follow you. Are you saying that the buyer is not paying a premium for Vivid's proprietary drivers or that the benefit of the proprietary driver is worth the premium charged? I assume you mean the latter because we all know Vivid loudspeakers are pricey. I am left to ask-how do you know that the benefit over off-the-shelf drivers is worth the tab? It seems an impossible thing to know. Only the developer could know and they will never be objective and neutral on the subject. i agree with those above that say that these alternative driver materials and design features are mostly for marketing-they create the "sizzle to the steak" that makes the buyer salivate and say, "I have got to have those!", while only conferring tiny incremental advantages or SQ improvements that could be far eclipsed by spending the dollars elsewhere. If money is of no consequence like to a Chinese billionaire, I can see going for it. For the rest of us, it makes little or no sense because for all of humankind, it's more a lateral move than a vertical one.

No... OEM does NOT mean made by the producer of the finished product. It only means the company that produced the equipment originally installed in the finished product. So for Wilson, OEM drivers would be SEAS, ScanSpeak, and Focal.

Uhh, yeah it mostly does. On a Ford, OEM means a fender or bumper cover or other genuine part made by them (though the part may be made for them by a subcontractor). Completely third party parts like tires are not OEM. SEAS, ScanSpeak, and Focal are not subcontractors, they are the equivalent of Firestone, Goodyear, and Michelin. Off the shelf, stock, or third-party. 

fsonicsmith,
Yes, I am saying that in the case of Vivid, the premium paid for their in-house designed drivers is worth the premium. They have pushed the boundaries in driver design, and it has paid off in pure and accurate reproduction. I don't own them, but I have heard them and I respect their achievement.