The "apparent wind champions" don't seem to have done any better than the "slow boat champions" over the last couple of ACs, and the only "multihull sailing champion" is long gone. Perhaps these guys are good enough to be able to develop new skills?
Sure they are good enough but the America's Cup has always had a trend to bias toward the "in crowd" mentality to a fault. While they have certainly invested in time, training, research, and design, I don't think they explored all the possible aspects of reaching out to existing multihull talent when they first switched to multihulls and we saw a lot of early rookie multihull mistakes. Regardless, Ashby, has demonstrated a real mastery for making fast boats fast. We'll never be able to put a number on how efficient NZ's wing trimming method is vs. Oracle's and we'll probably never even get a technical breakdown of the trimming system. In that vein, my opinion about Ashby is just opinion.
Who you are talking about "multihull sailing champion" that is long gone? Practically everyone in the America's Cup has come up from monohull and dinghy sailing with the exception of the French Team who, nationally, have embraced big multihull racing more strongly in the past. I don't think their performance is reflective of their talent but is more a reflection of their lack of funds.