Ditto to all above from several years in Melbourne. Even (never cheap) marina dockage along the waterway isn't without nuisance/danger... can be quite rough.
Sometimes even free is too much to pay for a boat. And after that nothing is free. There must be a hundred or more neglected/abandoned dreamboats more or less afloat along the stretch from Melbourne to Ft Pierce alone.
needs will be multiplied in the water compared to the dirt. Add the inconvenience or outright hassle of having to dinghy
out to the boat and you have a recipe for neglect.
Take a drive to any haulout facility anywhere and count the broken dreams.
Enthusiasm is a fragile thing.