You are right. Some of those people might even live on their boats.
As a matter of fact, the neighbor that used to live next door to me until April of this year bought a sailboat for him and his family to cruise around the world. I spoke to him about a month ago and they are currently in Cape Town. Apparently, they will leave Cape Town by end of November and come past here (Durban) on their way to Richardsbay on the Noth Coast. I don't know yet where they would be heading after that.
But as you say, it's expensive. He sold two of his three farms, bought the boat, and now they are living on the boat.