I'd say most of these criticisms of boat ownership are nullified when you're actually living on the boat, though. The average boat owner buys a boat, enjoys it every weekend for two months, then every second weekend for the next two months, then every month for the next year, and never gets as much use out of it as they thought they would.
If you're gonna live aboard, though... it's probably cheaper than a house.
I don't think I'd do it myself, though. I'm just not a boat person. If I ever buy a stupid money hole it'll be an aeroplane.