Someone is or actually was buying them. Lots of Bayliner 4788's out there.
You have to think of the demographics to rationalize a boat buyer with a $500K budget. Remember most large boats are financed.
My guess is...
Probably early to mid 50's in age.
Probably either no mortgage or a old mortgage close to being paid off and representing the price of homes 20 years ago.
Probably empty nester
Probably never had to start over due to divorce.
By the time someones in their 50's their probably at the director of VP level at their work. At the top of their game career wise. This is their time of life for disposable income.
Probably not a tinkerer any more due to career choices and moving up the ladder, so buying a new boat with no problems sounds appealing.
All this makes for the perfect, in my opinion $500,000 new boat buyer.
10-20% down, payments over 15 years on a new boat loan. Yes the cost is high, but its the time of life they can afford it.
Yep, if I were making $500K boats that's the guy I'd be targeting with my advertising.
I'd appeal to his sense of "if not now when?" and "you've earned it".