With regards to individual components, there's no such thing as state of the art, however, I do think there are SOTA music reproduction systems. I reason that components can only be heard in the context of systems. At the extreme high-end I am told that the synergy between components is critical to maximizing, as opposed to getting to the 90% level of musical performance. It's therefore possible that an individual component might perform at the SOTA level in one system, but only at an excellent level in another system. From this I conclude individual components cannot be truly SOTA. (I obviously place a high value on a component's ability to perform at its peak in a wide variety of systems.) I suspect that a near infinite variety of SOTA systems can be assembled. These systems would be able to provide the best available music reproduction currently available. I cannot prove it, but in these SOTA systems, the room design and system setup will be more important than what IC, resistor, tube or capcitor is within the boxes.
What equipment is state of the art?
What do you really consider to be state of the art? Innovative design with average parts quality? Or basic design principles with top shelf expensive parts? List some examples. One example might be Sony DSD; innovative design with average parts quality that many audiophiles are paying to upgrade.