That’s how it was done 30 years ago. My friend built his basement around the TV so it would be in the wall and he had a room behind it for all the cables and equipment.

My house has it too. It’s not a full room but a cut out with a door. Because originally if there was a big TV there would be no way to get behind it.

What’s up with that doorknob?

Some did that with speakers too back in the day (infinite baffle).

“It’s nice, but it takes up too much space in the bathroom.”

*TVs