No. Yaw is not apparent wind.

Agreed, apparent wind is not crosswind.

However, rarity of apparent wind angles in excess of 30 degrees is a realitive term. The lower bike speed the more common the occurance. Needless to say, far more riding is done at lower speeds. In any event, it would be interesting to see how bladed spokes performed beyond their laminar flow separation angle. At that point ovals are underperforming simple round DT spokes. That would present an unimpressive graph, a disadvantage if one is marketing oval spokes. At what, four times the price.