This is the lump of labor fallacy in reverse isn't it? Those people would eventually be employed by other industries - both the labor and $ formerly going to yachts would be used somewhere else.

In a democracy, ultimately the public should get to decide. Even if "taxing yachts" is not a win for the economy it might be a win for society. The USA is way too timid when it comes to using the tax code to incentivize and shape companies' and people's behavior. We really need to "re-internalize" the costs that big business and the rich externalize onto the public, and one way to do this is to impose very narrowly-directed taxes at things that the public bears but doesn't benefit from.