But, would the sort of person who owns a 1959 Ferrari want an "average yacht" ? I don't think so.
Yacht is a purpose classification, there are little boats in my local habour that a couple of old people drive out into the open water every weekend in the summer, and then there's something like Britannia, the ex-Royal Yacht that is a permanent floating museum in Edingburgh. Both are yachts because they are (or in Britannia's case were) for the pleasure use of the owners rather than being military, transport or for any commercial purpose.
So it's not difficult _at all_ to spend $100M on a yacht, whereas it's pretty tricky to do that for a car.
Worse, unlike cars as yachts grow more expensive a staff becomes at first a good idea and then essential - even if you barely use it you may be spending $1M plus per year on staff.
A 1959 Ferrari for example was sold for $18 million.