Last time around this phenomenon led to some REALLY bad sailboats as the manufacturers (Bayliner, Reinell) tried to get into the sailboat business as a survival tactic... Not seeing that this time around.
What I have noticed this past season is more planing-capable powerboats rumbling along at 8 knots or so.... a sudden interest in seeing the sights? or a keener eye on the gas gauge?
Looking around our area it doesn't really look like the high end powerboat market is slowing down... I guess if you can lay out that kind of cash the fuel costs are incidental.