You can't make a Taylor into "an iconic acoustic guitar" any more than you can make Yamaha into "an iconic grand piano." That belongs to Steinway, just as "Iconic acoustic guitar" belongs to Martin. Sure, you can claim some specific Taylor is their most popular or best known guitar. But "iconic" just isn't there.
Of course, that "status" has nothing to do with the fact that the quality of a current Taylor guitar/Yamaha grand piano may, by some, be considered better than a current Martin or a Steinway because "iconic" is about image. It is the same as comparing a Honda NSX with a Ferrari 308. The NSX may be (IS, in my opinion) a "better" car but the 308 is iconic. Most people wouldn't know an NSX if they saw one. Iconic is ONLY about an image; it has nothing to do with what product is really "better."