Seriously. This is so nonsensical and not even remotely related to anything.
These types of properties are often "purchased" by entities other than the owner for tax reasons. Many, many of the homes in these areas, even at prices half of what these cost, are owned by a corporation, trust, or LLC.
Also, many people buy houses to rent in this area. It's very common for someone to be renting a 5 bedroom house long term. I actually have one on my street: it's a 5,000 SF house rented by a couple in their 50's who have never owned. They like having the freedom but don't want to be in an apartment or condo. They rent a house 5-7 years, get bored and move neighborhoods.
Oh, and the house they are renting? It's owner is an LLC.
So this brings NOTHING to this discussion.