Don W wrote:

Its not at all unusual for people with significant net worth to
"self-insure".
A lot of companies do that as well.

It's not unusual for them to "self-drive" onto the rocks, either! I see or hear
of such an incident with a multi-million dollar boat every summer.

Sorry, couldn't resist that one...

Insurance companies are primarily for people who can't afford to take
the loss
should it happen. If you are willing to lose the boat without crying
over it, and
are financially able to take care of any damage you might cause to
others property, you don't need insurance.

In principle this is true, but the fact is there are not many people financially
prepared for such incidents. Besides property damage, you have to consider
personal injury, legal bills, environmental cleanup costs, etc. Even with all
the $0.5-2M boats out there, which seem mainstream nowadays, the people willing
and able to expose themselves to this kind of liability are vanishingly few.
People with that kind of money have a lot more to lose, too, and/or a lot more
to sue for.

Matt O.