A butler/house servant is not inherently cheap or productive to the owner anyways... economic reality doesn't matter here.
Economics suggest private jets are highly inefficient and having two for the same owner is simply silly. I remember this one guy who lost $30 billion in the American real estate bubble and in an interview said he assured his wife they were still stupidly rich and didn't need to conserve money. His wife won the argument and he sold all but one of his jets, which he left as "just in case" because they take commercial first class as much as possible instead of the private jet.
That was a tangent. My point being, if something is legal and helpful to the rich, it can exist regardless of how efficient it is.
Economics suggest private jets are highly inefficient and having two for the same owner is simply silly. I remember this one guy who lost $30 billion in the American real estate bubble and in an interview said he assured his wife they were still stupidly rich and didn't need to conserve money. His wife won the argument and he sold all but one of his jets, which he left as "just in case" because they take commercial first class as much as possible instead of the private jet.
That was a tangent. My point being, if something is legal and helpful to the rich, it can exist regardless of how efficient it is.