> I'm guessing that most rich people do not want the inside of their mansions to appear on a YouTube channel, especially one about mansions.
1. He doesn't film these walk-throughs himself. Real-estate agents film walk-throughs of these places to try to get them sold (it's well worth it for the commission they'll make), post them publically, and then he reviews those videos.
2. The homes in the walk-throughs are always vacant; there are no actual rich people involved to worry about their privacy. (They do almost look lived-in, yes, but that's all stuff that comes with the house. Not even staged; a lot of it is "design flourishes" added by the developer to match the architectural style.)
> Most of these mansions do not cost even US$100M and so probably do not belong to truly rich people.
When this guy records a review, it's to point out the flaws in a property's architecture + developer-furnished interior design. (Because that's the professional service he offers to his clients: inspecting properties for design flaws that lower the place's perceived resale value. His videos are a demonstration of that service.)
Thus, due to needing something worth spending 10 minutes talking about, the mansions he bothers to cover are always the ones that are badly designed.
My understanding is that these mansions exist in markets, and are built at scales, such that they actually should cost a lot more than they do. But their bad design has caused them to sit on the market for a long time; and that means the seller often gets desperate and lowers the price. (This isn't speculation; he often covers the market offer-price + resale-price history of a property as well.)
That being said, they still have all the features a truly-rich-person mansion should have. That stuff repeats over and over; you recognize it like MVC in software. These places are just the architectural equivalent of spaghetti code, putting things in inconvenient arrangements (I recall a recent review of a property where you had to walk down three hallways and cross two great rooms to get from the dining room to the nearest bathroom), stacking things so that rooms you'll spend a lot of time in don't have a great view (another property built into a hill made two bedrooms sub-grade with window wells, rather than just putting the bedrooms on the other side under the living room, where they'd get a panoramic picturesque view), and so on.