They tried that, back in November 1991.
https://en.wikipedia.org/wiki/Luxury_tax#United_States
It covered more than just yachts, but the biggest loser was the yacht industry, which saw sales plummet:
[quoting wikipedia]: The federal government estimated that it would raise $9 billion in excess revenues over the following five-year period. However, only two years after its imposition, in August 1993, at the behest of the luxury yacht industry, President Bill Clinton and Congress eliminated the "luxury tax" citing a loss in jobs.[6]
Atwood, Liz. "Boat dealers predict sales increase Luxury tax repeal helps ANNE ARUNDEL COUNTY BUSINESS". baltimoresun.com. Retrieved 23 August 2019.
[end wikipedia quote]
It turns out that luxuries are just that, luxuries, and the rich were more than willing to "do without" yet another yacht (or other luxury good) while the tax was on the books, and the tax never netted the "budget gains" its proponents predicted it would net, due to sales of all the taxed goods dropping off precipitously.