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.
Has the AC always favoured the in-crowd? Eons ago they pulled in people like Charlie Barr (a Scot) to drive defenders. The French pulled in Elvstrom in the '60s (although he dropped out due to nationality issues). Ted Turner came in from the wrong sort of boat and the wrong part of the country. Dennis Connor was a blow-in from California Star sailing. The second Endeavour challenge had a bunch of dinghy sailors. The second British 12 Metre challenge had a dinghy sailor driving. Ben Lexcen was an outsider in design terms, as was Bond. Key guys in Aus 2 like Grant Simmer were not even in the 'in crowd' in Sydney dinghy sailing.
In the early days multihull experts like Loick Peyron were called in - his team got last first time around. This time one of the world's great sailors, Cammas, got last in the ACWS on ONE DESIGN boats and last in the real AC. In the ACWS, when there was no design advantage because the boats were one design, the result was the same as it was in the cats last time around - teams with backgrounds in Etchells, Lasers and Finns dominated. That's only to be expected in some ways - monos make up about 95% of the racing scene, and slower monos like Etchells, Lasers and Finns make up a very big proportion of the rest. It's only logical that the type that has by far the largest pool of sailors will end up with the largest pool of talent.
It was interesting that when the AC was moved to foiling cats, people like Outteridge, Slingsby and Burling got into cats and/or foilers. Tom is apparently too heavy to keep up downwind in Moths, but he did very well upwind. Maybe the lesson to be learned is that good sailors can move from one extreme to the other pretty easily, and that if multihull sailors want to be asked into the afterguard of AC boats they should also do some cross-training to show how good they are?